Automotive passenger restraint and protection apparatus

ABSTRACT

An automotive passenger restraint and protection device for an automotive vehicle has a seatbelt which restrains an occupant of the automotive vehicle. The device includes an electric retractor, a power supply, a detector, first and second switches and a controller. The controller is responsive to the detector and controls the second switch to provide power to the electric retractor, controls the first switch to stop the supply of power through the first switch after power is supplied through the second switch, and controls the second switch to stop the supply of power through the second switch after a predetermined amount of time has elapsed after the first switch stops providing power.

This is a Division of application Ser. No. 10/385,811 filed Mar. 11,2003, now U.S. Pat. No. 6,843,339, which is a Division of applicationSer. No. 09/862,052 filed May 21, 2001, now U.S. Pat. No. 6,561,299issued May 13, 2003, which is a Division of application Ser. No.09/207,911 filed Dec. 9, 1998, now U.S. Pat. No. 6,257,363 issued Jul.10, 2001.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an automotive passenger restraint andprotection apparatus for automotive vehicles such as automobiles, whichuses an electric retracting and protracting a seatbelt for an occupant(driver or passenger).

2. Prior Art

An automotive passenger restraint and protection apparatus isconventionally known, which has an electric retractor which protractsand retracts a seatbelt. The electric retractor has driving meansformed, e.g. of an electric motor (hereinafter referred to as “motor” or“DC motor”) for driving the electric retractor.

In the conventional automotive passenger restraint and protectionapparatus of this type, fault diagnosis of the apparatus is carried outby pulling out or releasing a seatbelt by the occupant to ascertainwhether the seatbelt can be actually protracted or retracted.

The above manner of fault diagnosis is unable to accurately detectfaults in a DC motor for driving the electric retractor and itsperipheral parts.

There have been proposed many other fault diagnosis methods forautomotive passenger restraint and protection apparatuses.

One of those conventional methods is a method of detecting temperaturein the vicinity of the motor by a temperature sensor or detectingcurrent flowing to the motor by a current detecting circuit, anddetermining by an MPU (Micro Processing Unit) of the apparatus thatthere is a fault in the apparatus when the detected temperature value orcurrent value continuously exceeds a predetermined value over apredetermined time period. Upon determination that there is a fault inthe apparatus, the MPU causes the motor to be stopped to prevent firingof the motor.

According to the above fault diagnosis method, however, if anabnormality occurs in a power transmission mechanism which transmits adriving force from the motor to a reel shaft which has the seatbeltwound thereon such that the power transmission cannot transmit thedriving force and accordingly the motor runs idle, the temperature inthe vicinity of the motor rises and the current flowing to the motorincreases but not to such a degree that the MPU can determine that thereis a fault or abnormality. Consequently, such a kind of abnormalitycannot be detected by the conventional fault diagnosis method.

Further, if no countermeasure is taken to eliminate such an abnormalityof the power transmission mechanism, the motor may have a shortenedeffective life.

On the other hand, if the motor for driving the electric retractor iscontinuously operated for a long time, the temperature of the motorrises and can exceed the withstand temperature so that the motor canbecome faulty.

The conventional automotive passenger restraint and protectionapparatus, however, is not provided with a function of preventing such akind of fault.

The conventional automotive passenger restraint and protectionapparatuses include a type which has a function of carrying out aseatbelt slackening operation for giving a predetermined amount oflooseness to the seatbelt if seatbelt attaching detecting means detectsthat the seatbelt has shifted from a state disconnected from theoccupant to a state attached to the occupant, and carrying out aseatbelt storing operation for storing the seatbelt into a retractedposition if the seatbelt attaching detecting means detects that theseatbelt has shifted from the attached state to the disconnected state.

Further, the conventional automotive passenger restraint and protectionapparatuses include a type which has a function of carrying out aseatbelt slackening operation of retracting the seatbelt to a retractionlimit position (hereinafter merely referred to as “limit” unlessotherwise specified) if the seatbelt is protracted by the occupant inattaching the seatbelt to his body, and then protracting the seatbelt soas to give a predetermined amount of looseness to the seatbelt.

If, however, the seatbelt attaching detecting means becomes faulty suchthat it always determines that the seatbelt is disconnected from theoccupant even when the seatbelt is attached to the occupant, theseatbelt slackening operation cannot be performed even when the seatbelthas been attached to the occupant, whereby a predetermined amount oflooseness cannot be given to the seatbelt, failing to providing acomfortable seatbelt wearing feeling for the occupant. Further, even ifthe seatbelt has shifted to the disconnected state from the attachedstate with the seatbelt attaching detecting means being faulty, theseatbelt storing operation cannot be performed, so that the seatbelt isheld in the disconnected or protracted state.

Conversely, if the seatbelt attaching detecting means becomes faultysuch that it always determines that the seatbelt is attached to theoccupant even when the seatbelt is disconnected from the occupant, theseatbelt slackening operation can be carried out while the seatbelt isin the stored state, failing to keep the seatbelt in a proper storedstate. Further, in this state, if the seatbelt is attached to theoccupant' body, a determination is made that the seatbelt has been,protracted from a state attached to the occupant, so that the seatbeltslackening operation is carried out. However, if then the seatbelt isdisconnected from the occupant, a determination is made that theseatbelt is attached to the occupant, so that the seatbelt storingoperation cannot be performed, whereby the seatbelt is held in theprotracted state.

Moreover, in the above type of automotive passenger restraint andprotection apparatus, the seatbelt is always given a fixed amount oflooseness irrespective of whether there is a fear of collision of theautomotive vehicle. Therefore, the above function is not perfect toproperly protect the occupant.

Further, in the conventional automotive passenger restraint andprotection apparatus, the power consumption of the MPU is notcontemplated. As a result, for example, the MPU operates so as toexhibit its full function even in the case where the full function ofthe MPU need not be exhibited.

On the other hand, an automotive passenger restraint and protectionapparatus is conventionally known, which is provided withdriving/traveling state detecting means which detects a collision dangerstate and a collision unavoidable state of the automotive vehicle, and adozing state of the driver.

According to this type of automotive passenger restraint and protectionapparatus, if the driving/traveling state detecting means detects thecollision danger state of the automotive vehicle or the dozing state ofthe driver, protraction and retraction of the seatbelt are alternatelycarried out at irregular time intervals so as to alert the occupant ordriver to the danger. Further, if the collision unavoidable state of theautomotive vehicle is detected, the seatbelt is retracted with apredetermined magnitude of retracting force so as to properly protectthe occupant upon a collision of the automotive vehicle.

In the conventional automotive passenger restraint and protectionapparatus, however, once the ignition switch of the automotive vehicleis turned on, electric power is supplied from the power supply all thetime thereafter, so that the electric power is consumed even when thedriving/traveling state detecting means need not be operated.

Further, the electric retractor is constructed such that oncedisconnection of the seatbelt from the occupant is detected, it retractsthe seatbelt into its fully retracted position.

Therefore, if the occupant once releases a tongue of the seatbelt from abuckle secured to the seat into a disconnected state and immediatelythen attaches the tongue of the seat to the buckle, he has to manuallyprotract the seatbelt against the retracting force of the electricretractor. Thus, a large force is required for protracting the seatbelt,and therefore a weak occupant who has degraded physical ability such asan advanced-age occupant takes long to mount the seatbelt onto his body.

Further, an automotive passenger restraint and protection apparatus hasbeen proposed, e.g. by Japanese Laid-Open Patent Publication (Kokai) No.9-175327, which includes an electric retractor, and collision dangerpredicting means, wherein the electric retractor operates in response toa signal indicative of collision danger from the collision dangerpredicting means, to cause vibration by alternately applying andreleasing pressure to and from the occupant through the seatbelt. Thisvibration is continued until a signal indicative of a collision beingunavoidable is received from the collision danger predicting means orthe signal indicative of collision danger ceases to be received.

The proposed automotive passenger restraint and protection apparatusare, however, required to be still improved in the following points.That is, the collision danger predicting means merely predicts orforesees a future phenomenon but cannot perfectly predict a futurephenomenon. Therefore, according to the proposed construction that stopsvibration by alternate application and release of pressure upon stoppingof receipt of the collision danger signal, the collision danger signalis not received even when there is still a possibility that the vehicleencounters a collision, so that the vibration is stopped. Thus,sufficient warning cannot be given to the occupant.

Further, in the conventional automotive passenger restraint andprotection apparatus, in the case where when the seatbelt is in a statedisconnected from the occupant, when the seat is protracted by theoccupant, the time period after the protraction of the seatbelt by theoccupant is stopped and before retraction of the seat is started by theelectric retractor is almost constant irrespective of the speed of theprotraction of the seatbelt by the occupant. More specifically, theoccupant with the seatbelt not attached to his body protracts theseatbelt in order to mount the seatbelt onto his body, and thereafterstops protracting the seatbelt since he cannot easily soon engage thetongue of the seatbelt with the buckle and hence takes time to mount theseatbelt onto his body. The time period after the stoppage ofprotraction of the seatbelt by the occupant and before retraction of theseatbelt by the electric retractor is started is set to a predeterminedfixed time period which corresponds to the expected time that theoccupant should take by trying to engage the seatbelt with the buckle.

However, if the occupant protracts the seatbelt without the intention ofmounting the seatbelt onto his body and then gets off the automotivevehicle and closes the door, retraction of the seatbelt by the electricretractor is not carried out over the set predetermined time period. Asa result, the protracted seatbelt can be caught in the door when theoccupant closes the door. On the other hand, in the case where theoccupant takes longer time than expected to mount the seatbelt onto hisbody, retraction of the seatbelt by the electric retractor can startbefore the occupant completes the mounting. Then, the occupant takeslong to mount the seatbelt onto his body due to the retracting force ofthe electric retractor.

The time period after the seatbelt is protracted by the occupant andbefore he closes the door after getting off the automotive vehiclevaries depending upon the occupant's physical ability. Generallyspeaking, in the case of an occupant having a high physical ability, thetime the occupant takes to get off the vehicle is short and the timeperiod after the occupant protracts and before he closes the door isshort, whereas in the case of an occupant having a low physical ability,the time the occupant takes to get off the vehicle is long and the timeperiod after the occupant protracts and before he closes the door islong. Further, generally speaking, the seatbelt protracting speed of anoccupant of a high physical ability is high, whereas that of an occupantof a low physical ability is low. Accordingly, generally, the timeperiod after stoppage of protraction of the seatbelt by the occupant andbefore completion of mounting of the seatbelt onto his body isrelatively short in the case of an occupant of a high physical ability,and relatively long in the case of an occupant of a low physicalability.

In the conventional automotive passenger restraint and protectionapparatus, however, the time period after the stoppage of protraction ofthe seatbelt by the occupant and before the start of retraction of theseat by the electric retractor is set to an almost constant valueirrespective of the physical ability of the occupant. Therefore, if theset time period is a relatively long time period corresponding to anoccupant of a low physical ability, when an occupant of a high physicalability gets off the vehicle and closes the door in a relatively shorttime, the seatbelt can be caught in the door, while if the set timeperiod is a relatively short time period corresponding to an occupant ofa high physical ability, when an occupant of a low physical abilitymounts the seatbelt onto his body, the seatbelt starts to be retractedby the electric retractor before he finishes mounting the seatbelt ontohis body, thus impeding the occupant's mounting motion.

Further, in the conventional automotive passenger restraint andprotection apparatus, supply voltage to the electric retractor issupplied from a battery provided in the automotive vehicle all the time,as known from Japanese Laid-Open Utility Model publication (Kokai) No.61-134464. Further, in the apparatus according to this publication, theseatbelt is not retracted after disconnection of the seatbelt from theoccupant.

According to this conventional automotive passenger restraint andprotection apparatus, however, since the supply voltage to the electricretractor is supplied from the batter all the time, the battery isconsumed even when the supply voltage need not be supplied to theelectric retractor, resulting in early deterioration of the battery.Further, since the seatbelt is not retracted after disconnection of theseatbelt from the occupant, there is a possibility that the tongue ofthe seatbelt can be caught in the door.

SUMMARY OF THE INVENTION

It is a first object of the invention to provide an automotive passengerrestraint and protection apparatus which is capable of achievingaccurate fault diagnosis of the apparatus.

A second object of the invention is to provide an automotive passengerrestraint and protection apparatus which is capable of performingaccurate fault diagnosis of the apparatus and giving warning upondetection of a fault to alert the occupant to the fault.

A third object of the invention is to provide an automotive passengerrestraint and protection apparatus which is capable of preventingdriving means for protracting and retracting the seatbelt from becomingfaulty.

A fourth object of the invention is to provide an automotive passengerrestraint and protection apparatus which is capable of providing acomfortable seatbelt attaching feeling and preventing the seatbelt frombeing damaged even when attaching or disconnection of the seatbelt to orfrom the occupant cannot be accurately detected due to a fault.

A fifth object of the invention is to provide an automotive passengerrestraint and protection apparatus which is capable of changing theoperative state of control means of the apparatus according to theexpected ability thereof to thereby reduce the power consumption.

A sixth an automotive passenger restraint and protection apparatus whichis capable of supplying

To attain the first object, according to a first aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising an electric retractor having drivingmeans for retracting and protracting the seatbelt, voltage waveformapplying means for applying voltage having a predetermined waveform tothe driving means, current waveform detecting means for detecting awaveform of current flowing to the driving means, and fault diagnosismeans for carrying out fault diagnosis of the driving means, based uponthe waveform of current detected by the current waveform detecting meanswhen the voltage waveform applying means applies the voltage having thepredetermined waveform to the driving means.

According to the first aspect, fault diagnosis of the driving means iscarried out based upon a waveform of current detected by the currentwaveform detecting means when the voltage waveform applying meansapplies voltage having a predetermined waveform to the driving means. Asa result, it is possible to determine whether the driving means isfunctioning normally or abnormally, in an electric manner, therebyachieving accurate fault diagnosis of the apparatus.

To attain the first object, according to a second aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising an electric retractor having drivingmeans for retracting and protracting the seatbelt, a load having loadcharacteristics equivalent to electrical characteristics of the drivingmeans, voltage waveform applying means for selectively selectivelyapplying voltage having a predetermined waveform to the driving meansand the load, current waveform detecting means for detecting a waveformof current flowing to the driving means or to the load, and faultdiagnosis means for carrying out fault diagnosis of the driving means,based upon the waveform of current detected by the current waveformdetecting means when the voltage waveform applying means applies thevoltage having the predetermined waveform to the driving means and thewaveform of current detected by the current waveform detecting meanswhen the voltage waveform applying means applies the voltage having thepredetermined waveform to the load.

According to the second aspect, fault diagnosis of the driving means iscarried out based upon a waveform of current detected by the currentwaveform detecting means when the voltage waveform applying meansapplies voltage having a predetermined waveform to the driving means anda waveform of current detected by the current waveform detecting meanswhen the voltage waveform applying means applies the voltage having thepredetermined waveform to the load. As a result, it is possible todetermine whether the driving means is functioning normally orabnormally, in an electric manner, thereby achieving accurate faultdiagnosis of the apparatus.

To attain the second object, according to a third aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising an electric retractor having drivingmeans for retracting and protracting the seatbelt, warning means forgiving warning upon occurrent of a fault of the driving means, controlmeans for controlling the driving means and the warning means, andterminal voltage measuring means for measuring terminal voltage acrossthe driving means, wherein the control means stops operation of thedriving means and causes the warning means to give warning when thedriving means has continued to operate over a predetermined time periodwhile the terminal voltage measured by the terminal voltage measuringmeans falls within a range between a first predetermined value and asecond predetermined value.

According to the third aspect, the control means stops operation of thedriving means and causes the warning means to give warning when thedriving means has continued to operate over a predetermined time periodwhile the terminal voltage measured by the terminal voltage measuringmeans falls within a range between a first predetermined value and asecond predetermined value. As a result, it is possible to performaccurate fault diagnosis of the apparatus and give warning upondetection of a fault to alert the occupant to the fault.

Preferably, the voltage range between the first predetermined value andthe second predetermined is a range that can be assumed when the drivingmeans runs idle while it is functioning normally.

To attain the second object, according to a fourth aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising an electric retractor having drivingmeans for retracting and protracting the seatbelt, warning means forgiving warning upon occurrent of a fault of the driving means, controlmeans for controlling the driving means and the warning means, andcurrent detecting means for detecting current flowing to the drivingmeans, wherein the control means stops operation of the driving meansand causes the warning means to give warning when the driving means hascontinued to operate over a predetermined time period while the currentdetected by the current detecting means falls within a range between afirst predetermined value and a second predetermined value.

According to the fourth aspect, the control means stops operation of thedriving means and causes the warning means to give warning when thedriving means has continued to operate over a predetermined time periodwhile the current detected by the current detecting means falls within arange between a first predetermined value and a second predeterminedvalue. As a result, it is possible to perform accurate fault diagnosisof the apparatus and give warning upon detection of a fault to alert theoccupant to the fault.

Preferably, the current range between the first predetermined value andthe second predetermined is a range that can be assumed when the drivingmeans runs idle while it is functioning normally.

To attain the third object, according to a fifth aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising an electric retractor having drivingmeans for retracting and protracting the seatbelt, supply voltagesupplying means for supplying supply voltage to the driving means,abnormality detecting means for detecting abnormality of the drivingmeans, and supply voltage decreasing means for decreasing the supplyvoltage supplied to the driving means by the supply voltage supplyingmeans when the abnormality of the driving means is detected by theabnormality detecting means.

According to the fifth aspect, the supply voltage supplied to thedriving means by the supply voltage supplying means is decreased whenabnormality of the driving means is detected by the abnormalitydetecting means. As a result, excessively high supply voltage is notapplied to the driving means to thereby prevent the driving means frombecoming faulty.

Preferably, the automotive passenger restraint and protection apparatusaccording to the fifth aspect includes current detecting means fordetecting current flowing to the driving means, and timer means formeasuring a time period during which the current detected by the currentdetecting means exceeds a predetermined value, and wherein theabnormality detecting means detects that the driving means is abnormalwhen the time period measured by the timer means exceeds a predeterminedtime period.

Also preferably, the automotive passenger restraint and protectionapparatus according to the fifth aspect includes tension detecting meansfor detecting tension of the seatbelt, and timer means for measuring atime period during which the tension detected by the tension detectingmeans exceeds a predetermined value, and wherein the abnormalitydetecting means detects that the driving means is abnormal when the timeperiod measured by the timer means exceeds a predetermined time period.

Also preferably, the automotive passenger restraint and protectionapparatus according to the fifth aspect includes torque detecting meansfor detecting rotational torque of the electric retractor, and timermeans for measuring a time period during which the rotational torquedetected by the torque detecting means exceeds a predetermined value,and wherein the abnormality detecting means detects that the drivingmeans is abnormal when the time period measured by the timer meansexceeds a predetermined time period.

Also preferably, the automotive passenger restraint and protectionapparatus according to the fifth aspect includes temperature detectingmeans for detecting temperature in a vicinity of the driving means ortemperature of the driving means, and timer means for measuring a timeperiod during which the temperature detected by the temperaturedetecting means exceeds a predetermined value, and wherein theabnormality detecting means detects that the driving means is abnormalwhen the time period measured by the timer means exceeds a predeterminedtime period.

To attain the fourth object, according to a sixth aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising a reel shaft having the seatbelt woundthereon, winding amount detecting means for detecting an amount ofwinding of the seatbelt on the reel shaft, driving means for rotatingthe reel shaft in a direction of retracting the seatbelt and in adirection of protracting the seatbelt, control means for controlling thedriving means, seatbelt attaching detecting means for detecting whetherthe seatbelt is attached to the occupant or disconnected from theoccupant, and fault detecting means for detecting a fault of theseatbelt attaching detecting means, wherein the control means controlsthe driving means according to the amount of winding of the seatbelt onthe reel shaft detected by the winding amount detecting means, when thefault of the seatbelt attaching detecting means is detected by the faultdetecting means.

According to the sixth aspect, the driving means is controlled accordingto an amount of winding of the seatbelt on the reel shaft detected bythe winding amount detecting means, when a fault of the seatbeltattaching detecting means is detected by the fault detecting means. As aresult, even when attaching or disconnection of the seatbelt to or fromthe occupant cannot be accurately detected due to a fault, if the amountof winding of the seatbelt detected by the winding amount detectingmeans is small, it is judged that the seatbelt is attached to theoccupant, and then the seatbelt is retracted to the retraction limit,followed by being given a predetermined amount of looseness. On theother hand, if the amount of winding of the seatbelt detected by thewinding amount detecting means is large, it is judged that the seatbeltis disconnected from the occupant, and then the seatbelt is stored intoits retracted position. Thus, even when attaching or disconnection ofthe seatbelt to or from the occupant cannot be accurately detected dueto a fault. It is possible to provide a comfortable seatbelt attachingfeeling and prevent the seatbelt from being damaged.

To attain the fifth object, according to a seventh aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising an electric retractor having drivingmeans for retracting and protracting the seatbelt, seatbelt attachingdetecting means for detecting attaching of the seatbelt to the occupantor disconnection of the seatbelt from the occupant, and seatbeltprotraction detecting means for detecting protraction of the seatbelt bythe occupant, and control means for controlling the driving means byperforming a plurality of functions, the control means having selectingmeans for selecting a reduced power consumption mode for permitting thecontrol means to perform at least one minimum required function of theplurality of functions so as to save power consumption by the electricretractor, or a normal power consumption mode for permitting the controlmeans to perform all of the plurality of functions so as not to savepower consumption by the electric retractor, wherein the selecting meansselects the reduced power consumption mode when a predetermined timeperiod has elapsed after detection of the disconnection of the seatbeltfrom the occupant by the seatbelt attaching detecting means while thenormal power consumption mode is selected, and selects the normal powerconsumption mode when the protraction of the seatbelt by the occupant isdetected by the seatbelt protraction detecting means or when theattaching of the seatbelt to the occupant is detected by the seatbeltattaching detecting means.

According to the seventh aspect, the reduced power consumption mode isselected when a predetermined time period has elapsed after detection ofdisconnection of the seatbelt from the occupant by the seatbeltattaching detecting means while a normal power consumption mode isselected, and the normal power consumption mode is selected whenprotraction of the seatbelt by the occupant is detected by the seatbeltprotraction detecting means or when attaching of the seatbelt to theoccupant is detected by the seatbelt attaching detecting means. Thus,the operative state of the control means can be changed according to theexpected ability thereof. As a result, it is possible to reduce thepower consumption.

To attain the sixth object, according to an eighth aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising an electric retractor having drivingmeans for retracting and protracting the seatbelt, vehicle stoppagedetecting means for detecting stoppage of the automotive vehicle,driving/traveling state detecting means for detecting states of drivingand traveling of the automotive vehicle by the occupant, supply meansfor supplying electric power to the driving/traveling state detectingmeans, and control means for controlling the supply means so as to stopsupply of the power to the driving/traveling state detecting means whenthe stoppage of the automotive vehicle is detected by the vehiclestoppage detecting means.

According to the eighth aspect, the supply means is controlled so as tostop supply of electric power to the driving/traveling state detectingmeans when stoppage of the automotive vehicle is detected by the vehiclestoppage detecting means. Thus, electric power is supplied to thedriving/traveling state detecting means only when the latter needs to beoperated, to thereby reduce the power consumption.

Preferably, the vehicle stoppage detecting means comprises at least oneof seatbelt attaching detecting means for detecting whether the seatbeltis attached to the occupant, shift position detecting means fordetecting whether a shift position of a transmission of the automotivevehicle is in a parking position, and parking brake detecting means fordetecting whether a parking brake of the automotive vehicle is operated.

To attain the seventh object, according to a ninth aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising an electric retractor having drivingmeans for retracting and protracting the seatbelt, control means forcontrolling the driving means, seatbelt protraction detecting means fordetecting protraction of the seatbelt by the occupant, and releasedetecting means for detecting release of the seatbelt from a stateattached to the occupant to a state disconnected from the occupant,wherein the control means controls the driving means so as to startretraction of the seatbelt when the release of the seatbelt is detectedby the release detecting means, controls the driving means so as to stopoperation thereof over a predetermined time at least one time after thestart of retraction of the seatbelt and before completion of theretraction, and controls the driving means so as to protract theseatbelt when the protraction is detected by the seatbelt protractiondetecting means within the predetermined time period.

According to the ninth aspect, the driving means is controlled so as tostart retraction of the seatbelt when release of the seatbelt isdetected by the release detecting means, then controlled so as to stopoperation thereof over a predetermined time at least one time after thestart of retraction of the seatbelt and before completion of theretraction, and controlled so as to protract the seatbelt whenprotraction of the seatbelt is detected by the seatbelt protractiondetecting means within the predetermined time period. As a result, theoccupant need not pull out or protract the seatbelt against theretracting force of the driving means, thereby facilitating mounting ofthe seatbelt onto the occupant.

To attain the eighth object, according to a tenth aspect of theinvention, the control means of the automotive restraint and protectionapparatus according to the ninth aspect controls the driving means so asto retract the seatbelt when the protraction is not detected by theseatbelt protraction detecting means within the predetermined timeperiod. This can avoid that the seatbelt is left in a protracted state,to thereby prevent the seatbelt from being caught in the door.

To attain the ninth object, according to an eleventh aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising danger degree determining means fordetermining a degree of danger of collision of the automotive vehicle,danger predicting means for predicting a possibility of collision of theautomotive vehicle, from the degree of danger determined by the dangerdegree determining means, collision danger signal generating means forgenerating a collision danger signal when the possibility of collisionis predicted by the danger predicting means, driving means responsive tothe collision danger signal, for carrying out alternate retraction andprotraction of the seatbelt, deceleration detecting means for detectingdeceleration of the automotive vehicle, and seatbelt driving controlmeans for controlling the driving means so as to continue the alternateretraction and protraction of the seatbelt without stopping same afterthe collision danger signal ceases to be generated and until thedeceleration of the automotive vehicle detected by the decelerationdetecting means exceeds a predetermined value.

According to the eleventh aspect, the driving means is controlled tocontinue alternate retraction and protraction of the seatbelt withoutstopping same even after the collision danger signal ceases to begenerated, so long as it is expected that the automotive vehicle runsinto danger, to thereby fully alert the occupant to the danger. Thus,the automotive restraint and protection apparatus can be utilized as awarning device.

To attain the seventh object, according to a twelfth aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising seatbelt attaching state detectingmeans for detecting whether the seatbelt is in a state attached to theoccupant or in a state disconnected from the occupant, seatbeltprotraction detecting means for detecting protraction of the seatbelt bythe occupant, seatbelt protraction stoppage detecting means fordetecting stoppage of protraction of the seatbelt, inhibiting means forinhibiting retraction of the seatbelt over a predetermined time periodafter the stoppage of protraction of the seatbelt is detected by theseatbelt protraction stoppage detecting means after the protraction ofthe seatbelt is detected by the seatbelt protraction detecting meanswhile the seatbelt is detected to be in the state disconnected from theoccupant by the seatbelt attaching state detecting means, protractingspeed detecting means for detecting speed of protraction of theseatbelt, and setting means for setting the predetermined time periodaccording to the speed of protraction of the seatbelt detected by theprotracting speed detecting means.

According to the twelfth aspect, a predetermined time period over whichretraction of the seatbelt is inhibited after stoppage of protraction ofthe seatbelt is detected following detection of the protraction of theseatbelt while the seatbelt is a state disconnected from the occupant,is set according to the speed of protraction of the seatbelt detected bythe protracting speed detecting means. As a result, even when anoccupant of a high physical ability gets off the vehicle and closes thedoor in a short time after protracting the seatbelt, it can be preventedthat the seatbelt is caught in the door. On the other hand, when anoccupant of a low physical ability mounts the seatbelt onto his body, itcan be prevented that the seatbelt starts to be retracted before hefinishes mounting the seatbelt onto his body to impede his moundingmotion, whereby mounting of the seatbelt onto the occupant isfacilitated.

Preferably, the setting means sets the predetermined time period to ashorter value as the speed of protraction of the seatbelt detected bythe protracting speed detecting means is higher, and to a longer valueas the detected speed of protraction of the seatbelt is lower.

To attain the tenth object, according to a thirteenth aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising a motor for retracting and protractingthe seatbelt, seatbelt attaching state detecting means for detectingwhether the seatbelt is in a state attached to the occupant or in astate disconnected from the occupant, danger degree detecting means fordetecting a significant degree of danger of collision of the automotivevehicle, and control means for controlling the motor so as to retractthe seatbelt to a limit thereof and then protract the seatbelt tothereby give a predetermined amount of looseness to the seatbelt,wherein the control means controls the motor so as to give a firstpredetermined amount of looseness to the seatbelt when the significantdegree of danger is not detected by the danger degree detecting meanswhile the seatbelt is detected to be in the state attached to theoccupant, and controls the motor so as to give a second predeterminedamount of looseness to the seatbelt which is smaller than the firstpredetermined amount of looseness when the significant degree of dangeris detected by the danger degree detecting means while the seatbelt isdetected to be in the state attached to the occupant.

According to the thirteenth aspect, the motor is controlled so as togive a first predetermined amount of looseness to the seatbelt when asignificant degree of danger is not detected by the danger degreedetecting means while the seatbelt is in a state attached to theoccupant, and controlled so as to give a second predetermined amount oflooseness to the seatbelt which is smaller than the first predeterminedamount of looseness when the significant degree of danger is detected bythe danger degree detecting means while the seatbelt is in the stateattached to the occupant. Thus, when no significant degree of danger isdetected, the first amount of looseness is given to the seatbelt,whereby the occupant does not have a feeling of oppression, and on theother hand, when the significant degree of danger is detected, thesecond amount of looseness is given to the seatbelt, whereby theoccupant can be properly protected. As a result, a comfortable seatbeltattaching feeling can be given to the occupant, while the occupant canbe properly protected.

To attain the eleventh object, according to a fourteenth aspect of theinvention, the danger degree detecting means of the automotive passengerrestraint and protection apparatus according to the thirteenth aspectcomprises at least one of vehicle speed detecting means for detectingtraveling speed of the automotive vehicle, braking detecting means fordetecting stepping-on of a brake pedal of the automotive vehicle,steering angle change rate detecting means for detecting a rate ofchange in a steering angle of the automotive vehicle, ambientilluminance detecting means for detecting ambient illuminance of theautomotive vehicle, and raindrop detecting means for detecting raindropson the automotive vehicle, the danger degree detecting means detectingthe significant degree of danger if the vehicle speed detecting meansdetects that the traveling speed of the automotive vehicle is higherthan a predetermined value and at the same time at least one ofconditions is satisfied that the stepping-on of the brake pedal isdetected by the braking detecting means, the steering angle change ratedetecting means detects that the rate of change of the steering angleexceeds a predetermined value, the ambient illuminance detecting meansdetects that the ambient illuminance of the automotive vehicle is belowa predetermined value, and the raindrop detecting means detects theraindrops on the automotive vehicle.

According to the fourteenth aspect, it is possible to accuratelydetermine the degree of danger of collision of the automotive vehicle.

To attain the twelfth object, according to a fifteenth aspect of theinvention, various forms of the automotive passenger restraint andprotection apparatus according to the fourteenth aspect are provided asfollows:

The danger degree detecting means comprises vehicle speed detectingmeans for detecting traveling speed of the automotive vehicle, andbraking detecting means for detecting a stepping-on force of a brakepedal of the automotive vehicle or stepping-on speed thereof, thecontrol means controlling the motor such that rotational speed of themotor in retracting the seatbelt is higher as the stepping-on force orthe stepping-on speed detected by the braking detecting means is larger,when the traveling speed of the automotive vehicle detected by thevehicle speed detecting means is higher than a predetermined value.

The danger degree detecting means comprises vehicle speed detectingmeans for detecting traveling speed of the automotive vehicle, andbraking detecting means for detecting stepping-on of a brake pedal ofthe automotive vehicle, the control means controlling the motor suchthat rotational speed of the motor in retracting the seatbelt is higheras the traveling speed of the automotive vehicle detected by the vehiclespeed detecting means is higher, when the detected traveling speed ishigher than a predetermined value and at the same time the stepping-onof the brake pedal is detected by the braking detecting means.

The danger degree detecting means comprises vehicle speed detectingmeans for detecting traveling speed of the automotive vehicle, andsteering angle change rate detecting means for detecting a rate ofchange in a steering angle of the automotive vehicle, the control meanscontrolling the motor such that rotational speed of the motor inretracting the seatbelt is higher as the rate of change in the steeringangle detected by the steering angle change rate detecting means islarger, when the traveling speed of the automotive vehicle detected bythe vehicle speed detecting means is higher than a predetermined value.

The danger degree detecting means comprises vehicle speed detectingmeans for detecting traveling speed of the automotive vehicle, andsteering angle change rate detecting means for detecting a rate ofchange in a steering angle of the automotive vehicle, the control meanscontrolling the motor such that rotational speed of the motor inretracting the seatbelt is higher as the traveling speed of theautomotive vehicle detected by the vehicle speed detecting means ishigher, when the detected traveling speed is higher than a predeterminedvalue and at the same time the rate of change in the steering angledetected by the steering angle change rate detecting means is largerthan a predetermined value.

The danger degree detecting means comprises vehicle speed detectingmeans for detecting traveling speed of the automotive vehicle, andambient illuminance detecting means for detecting ambient illuminance ofthe automotive vehicle, the control means controlling the motor suchthat rotational speed of the motor in retracting the seatbelt is higheras the ambient illuminance detected by the ambient illuminance detectingmeans is smaller, when the traveling speed of the automotive vehicledetected by the vehicle speed detecting means is higher than apredetermined value.

The danger degree detecting means comprises vehicle speed detectingmeans for detecting traveling speed of the automotive vehicle, andambient illuminance detecting means for detecting ambient illuminance ofthe automotive vehicle, the control means controlling the motor suchthat rotational speed of the motor in retracting the seatbelt is higheras the traveling speed of the automotive vehicle detected by the vehiclespeed detecting means is higher, when the detected traveling speed ishigher than a predetermined value and at the same time the ambientilluminance detected by the ambient illuminance detecting means issmaller than a predetermined value.

The danger degree detecting means comprises vehicle speed detectingmeans for detecting traveling speed of the automotive vehicle, andraindrop detecting means for detecting raindrop on the automotivevehicle, the control means controlling the motor such that rotationalspeed of the motor in retracting the seatbelt is higher as the travelingspeed of the automotive vehicle detected by the vehicle speed detectingmeans is higher, when the detected traveling speed is higher than apredetermined value and at the same time the raindrops are detected bythe raindrop detecting means.

The danger degree detecting means comprises vehicle speed detectingmeans for detecting traveling speed of the automotive vehicle, andbraking detecting means for detecting a stepping-on force of a brakepedal of the automotive vehicle or stepping-on speed thereof, thecontrol means controlling the motor such that an amount of protractionof the seatbelt is smaller as the stepping-on force or the stepping-onspeed detected by the braking detecting means is larger, when thetraveling speed of the automotive vehicle detected by the vehicle speeddetecting means is higher than a predetermined value.

The danger degree detecting means comprises vehicle speed detectingmeans for detecting traveling speed of the automotive vehicle, andbraking detecting means for detecting stepping-on of a brake pedal ofthe automotive vehicle, the control means controlling the motor suchthat an amount of protraction of the seatbelt is smaller as thetraveling speed of the automotive vehicle detected by the vehicle speeddetecting means is higher, when the detected traveling speed is higherthan a predetermined value and at the same time the stepping-on of thebrake pedal is detected by the braking detecting means.

The danger degree detecting means comprises vehicle speed detectingmeans for detecting traveling speed of the automotive vehicle, andsteering angle change rate detecting means for detecting a rate ofchange in a steering angle of the automotive vehicle, the control meanscontrolling the motor such that an amount of protraction of the seatbeltis smaller as the rate of change in the steering angle detected by thesteering angle change rate detecting means is larger, when the travelingspeed of the automotive vehicle detected by the vehicle speed detectingmeans is higher than a predetermined value.

The danger degree detecting means comprises vehicle speed detectingmeans for detecting traveling speed of the automotive vehicle, andsteering angle change rate detecting means for detecting a rate ofchange in a steering angle of the automotive vehicle, the control meanscontrolling the motor such that an amount of protraction of the seatbeltis smaller as the traveling speed of the automotive vehicle detected bythe vehicle speed detecting means is higher, when the detected travelingspeed is higher than a predetermined value and at the same time the rateof change in the steering angle detected by the steering angle changerate detecting means is larger than a predetermined value.

The danger degree detecting means comprises vehicle speed detectingmeans for detecting traveling speed of the automotive vehicle, andambient illuminance detecting means for detecting ambient illuminance ofthe automotive vehicle, the control means controlling the motor suchthat an amount of protraction of the seatbelt is smaller as the ambientilluminance detected by the ambient illuminance detecting means issmaller, when the traveling speed of the automotive vehicle detected bythe vehicle speed detecting means is higher than a predetermined value.

The danger degree detecting means comprises vehicle speed detectingmeans for detecting traveling speed of the automotive vehicle, andambient illuminance detecting means for detecting ambient illuminance ofthe automotive vehicle, the control means controlling the motor suchthat an amount of protraction of the seatbelt is smaller as thetraveling speed of the automotive vehicle detected by the vehicle speeddetecting means is higher, when the detected traveling speed is higherthan a predetermined value and at the same time the ambient illuminancedetected by the ambient illuminance detecting means is smaller than apredetermined value.

The danger degree detecting means comprises vehicle speed detectingmeans for detecting traveling speed of the automotive vehicle, andraindrop detecting means for detecting raindrops on the automotivevehicle, the control means controlling the motor such that an amount ofprotraction of the seatbelt is smaller as the traveling speed of theautomotive vehicle detected by the vehicle speed detecting means ishigher, when the detected traveling speed is higher than a predeterminedvalue and at the same time the raindrops are detected by the raindropdetecting means.

According to the fifteenth aspect, it is possible to properly protectthe occupant in a manner dependent upon the degree of danger ofcollision of the automotive vehicle.

To attain the thirteenth object, according to a sixteenth aspect of theinvention, there is provided an automotive passenger restraint andprotection apparatus for an automotive vehicle, having a seatbelt, forrestraining an occupant of the automotive vehicle by the seatbelt toprotect the occupant, comprising an electric retractor having drivingmeans for retracting and protracting the seatbelt, power supply meansfor supplying power to the electric retractor, detecting means fordetecting whether there is a need for supply of power from the powersupply means to the electric retractor, first switching means responsiveto results of detection of the detecting means, for selecting supply ofpower from the power supply means to the electric retractor and stoppageof the supply of power, second switching means for selecting supply ofpower from the power supply means to the electric retractor and stoppageof the supply of power, and monitor control means for monitoring theresults of detection of the detecting means and controlling the secondswitching means in response to the results of detection of the detectingmeans, wherein the monitor control means is responsive to a result ofdetection of the detecting means that there is no need for supply ofpower from the power supply means to the electric retractor after supplyof power from the power supply means to the electric retractor, forcontrolling the second switching means so as to start supply of powerfrom the power supply means to the electric retractor, and following thestart of supply of power by the second switching means, the firstswitching means stops the supply of power to the electric retractor inresponse to the result of detection of the detecting means, and whereinthe monitor control means controls the second switching means so as tostop the supply of power to the electric retractor after lapse of apredetermined time period from the stoppage of the supply of power bythe first switching means.

According to the sixteenth aspect, when the detecting means detects thatthere is no need for supply of power from the power supply means to theelectric retractor after supply of power from the power supply means tothe electric retractor, the first switching means stops the supply ofpower to the electric retractor in response to the result of detectionof the detecting means. As a result, wasteful consumption anddeterioration of the battery can be prevented.

Further, when the detecting means detects that there is no need forsupply of power from the power supply means to the electric retractorafter supply of power from the power supply means to the electricretractor, the monitor control means controls the second switching meansto start supply of power from the power supply means to the electricretractor, and after lapse of a predetermined time period from thestoppage of the supply of power by the first switching means, themonitor control means controls the second switching means to stop thesupply of power to the electric retractor. As a result, retraction ofthe seatbelt can be carried out without fail when the seatbelt isdisconnected from the occupant, to thereby prevent the seatbelt tonguefrom being caught in the door.

The above and other objects, features, and advantages of the inventionwill become more apparent from the following detailed description takenin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram schematically showing the arrangement of anelectric retractor 100 provided in an automotive passenger restraint andprotection apparatus according to a first embodiment of the invention;

FIG. 2 is a circuit diagram showing the configuration of a DC motordriver 11 appearing in FIG. 1;

FIG. 3 is a flowchart showing a fault diagnosis program according to thefirst embodiment, executed by an MPU 14 appearing in FIG. 1;

FIG. 4A is a graph showing an example of the waveform of voltage acrossterminals P3 and P4;

FIG. 4B is a graph showing another example of the waveform of voltageacross terminals P3 and P4;

FIG. 5 is a flowchart showing a fault diagnosis program according to asecond embodiment of the invention, executed by the MPU 14;

FIG. 6 is a flowchart showing the configuration of a DC motor driver 11employed in a third embodiment of the invention;

FIG. 7 is a flowchart showing a fault diagnosis program according to thethird embodiment of the invention, executed by the MPU 14;

FIG. 8 is a flowchart showing a fault diagnosis program according to afourth embodiment of the invention executed by the MPU 14;

FIG. 9 is a flowchart showing another fault diagnosis program accordingto the fourth embodiment;

FIG. 10 is a block diagram schematically showing the arrangement of anelectric retractor 500 provided in an automotive passenger restraint andprotection apparatus according to a fifth embodiment of the invention;

FIG. 11 is a flowchart showing a main status control program accordingto the fifth embodiment, executed by the MPU 14;

FIG. 12 is a flowchart showing a status control program executed at astep S1201 in FIG. 11;

FIG. 13 is a flowchart showing a status control program executed at astep S1202 in FIG. 11;

FIG. 14 is a flowchart showing a status control program executed at astep S1203 in FIG. 11;

FIG. 15 is a flowchart showing a status control program executed at astep S1204 in FIG. 11;

FIG. 16 is a block diagram schematically showing the arrangement of anelectric retractor 600 provided in an automotive passenger restraint andprotection apparatus according to a sixth embodiment of the invention;

FIG. 17 is a view showing an example of the waveforms of signals inputto the MPU 14 when a buckle connection detector 16 is normal;

FIG. 18 is a flowchart showing seatbelt storing control according to thesixth embodiment;

FIG. 19 is a view showing an example of the waveforms of signals inputto the MPU 14 when “ON fault” occurs with the seatbelt disconnected fromthe occupant;

FIG. 20 is a flowchart showing a control program according to the sixthembodiment, executed by the MPU 14;

FIG. 21 is a flowchart showing a continued part of the FIG. 20 control;

FIG. 22 is a flowchart showing timer interrupt processing according tothe sixth embodiment;

FIG. 23 is a flowchart showing seatbelt slackening control according tothe sixth embodiment;

FIG. 24 is a view showing an example of the waveforms of signals inputto the MPU 14 when “ON fault” occurs after the seatbelt shifts from astate attached to the occupant to a state disconnected from theoccupant;

FIG. 25 is a flowchart showing a control program executed by the MPU 14according to the sixth embodiment;

FIG. 26 is a flowchart showing a continued part of the FIG. 25 program;

FIG. 27 is a view showing an example of the waveforms of signals inputto the MPU 14 when “OFF fault” occurs with the seatbelt disconnectedfrom the occupant;

FIG. 28 is a flowchart showing a control program executed by the MPU 14according to the sixth embodiment;

FIG. 29 is a view showing an example of the waveforms of signals inputto the MPU 14 when “OFF fault” occurs after the seatbelt shifts from astate attached to the occupant to a state disconnected from theoccupant;

FIG. 30 is a flowchart showing a control program executed by the MPU 14according to the sixth embodiment;

FIG. 31 is a circuit diagram showing the arrangements of a DC motordriver 11 a detecting circuit 45 and a buckle connection detector 16according to a seventh embodiment of the invention;

FIG. 32A is a view showing a change in a signal input to the MPU 14 toindicate a normal power consumption mode;

FIG. 32B is a view showing a change in the signal input to the MPU 14 toindicate a reduced power consumption mode;

FIG. 32C is a view showing a low level at which the signal input to theMPU 14 is held to indicate no change in the power consumption mode;

FIG. 32D is a view showing a high level at which the signal input to theMPU 14 is held to indicate no change in the power consumption mode;

FIG. 33 is a flowchart showing reduced power consumption controlexecuted by the MPU 14 according to the seventh embodiment;

FIG. 34 is a block diagram showing the arrangement of an electricretractor 800 provided in an automotive passenger restraint andprotection apparatus according to an eighth embodiment of the invention;

FIG. 35 is a flowchart showing seatbelt storing control according to aninth embodiment of the invention executed by the MPU 14 in retractingthe seatbelt;

FIG. 36 is a flowchart showing seatbelt protraction control according tothe ninth embodiment executed by the MPU 14 in protracting the seatbelt;

FIG. 37 is a block diagram showing the arrangement of an automotivepassenger restraint and protection apparatus according to a tenthembodiment of the invention;

FIG. 38 is a block diagram showing details of the arrangement of theautomotive passenger restraint and protection apparatus according to thetenth embodiment;

FIG. 39A is a schematic view showing the construction of a seatbeltdevice with an electric retractor according to the tenth embodiment;

FIG. 39B is a schematic view showing the construction of the seatbeltdevice of FIG. 39A, as viewed from a different angle;

FIG. 40 is a flowchart showing a manner of operation of the automotivepassenger restraint and protection apparatus according to the tenthembodiment;

FIG. 41A is a diagram showing an example of the waveform of terminalvoltage across the DC motor 10 assumed when the seatbelt is slowlyprotracted by the occupant;

FIG. 41B is a diagram showing an example of the waveform of terminalvoltage across the DC motor 10 assumed when the seatbelt is quicklyprotracted by the occupant;

FIG. 42 is a flowchart showing a control program according to theeleventh embodiment, executed by the MPU 14;

FIG. 43 is a block diagram showing the arrangement of an arithmeticprocessing portion of the apparatus according to the eleventhembodiment;

FIG. 44 is block diagram showing the arrangement of an electricretractor 1200 according to a twelfth embodiment of the invention;

FIG. 45 is a schematic view showing the interior of a vehiclecompartment with a brake pedal, which is applied to the twelfthembodiment of the invention;

FIG. 46 is a flowchart showing a control program according to thetwelfth embodiment, executed by the MPU 14;

FIG. 47 is a flowchart showing first seatbelt slackening controlaccording to the twelfth embodiment;

FIG. 48 is a flowchart showing second seatbelt slackening controlaccording to the twelfth embodiment;

FIG. 49 is a schematic view showing the arrangement of an automotivepassenger restraint and protection apparatus according to a thirteenthembodiment of the invention;

FIG. 50 is a schematic view showing an occupant seat with a seatingswitch 104;

FIG. 51 is a schematic view showing the occupant seat as viewed from adifferent angle; and

FIG. 52 is a schematic sectional view showing the construction of theseating switch 104.

DETAILED DESCRIPTION

The invention will now be described in detail with reference to drawingsshowing embodiments thereof.

First Embodiment

Referring first to FIG. 1, there is shown the arrangement of an electricretractor 100 provided in an automotive passenger restraint andprotection apparatus according to a first embodiment of the invention.

The seatbelt retractor 100 has a frame 1 in which is rotatably mounted areel shaft (takeup shaft) 3 for retracting and protracting a seatbelt.Secured to an end of the reel shaft 3 is a known seatbelt lockingmechanism 2 which is adapted to lock or stop the seatbelt from beingprotracted when a predetermined or higher degree of deceleration isapplied to an automotive vehicle in which the present apparatus isinstalled or when the seatbelt is protracted at a predetermined orhigher degree of acceleration.

The reel shaft 3 has a central shaft 3 a coupled to a central shaft of areel shaft pulley 5, which is in turn coupled to a DC motor pulley 6 viaa power transmission belt 7.

The reel shaft pulley 5 and the DC motor pulley 6 each have an outerperiphery thereof formed with a predetermined number of outer teeth,while the power transmission belt 7 has an inner periphery thereofformed with a predetermined number of inner teeth which are in mesh withthe outer teeth of the reel shaft pulley 5 and the DC motor pulley 6.

The DC motor pulley 6 has a central shaft thereof coupled to a DC motor10 such that the rotation of the DC motor 10 is transmitted to the reelshaft 3 via the DC motor pulley 6.

The DC motor 10 is fixed to the frame 1 at least two points thereof, andis connected to an MPU (Micro Processing Unit) 14 via a DC motor driver11 which rotatively drives the DC motor 10 in response to a PWM (PulseWidth Modulation) signal from the MPU 14.

FIG. 2 is a circuit diagram showing the construction of the DC motordriver 11. In FIG. 2, reference numerals P1 and P2 designate inputterminals for the PWM (Pulse Width Modulation) signal from the MPU 14,which has a frequency of 20 kHz, for example. Reference numerals P3 andP4 designate output terminals for detecting current, and P5 and P6output terminals for detecting voltage, the terminals P1 to P6 beingconnected to the MPU 14. Supply voltage from a battery Vb shown in FIG.2 is supplied to the DC motor 10. A plurality of transistors and FETsappearing in FIG. 2 are for selectively causing the DC motor 10 to benormally rotated or reversely rotated in response to the PWM signal fromthe MPU 14. More specifically, the DC motor driver 11 is constructedsuch that if a high-level control signal is delivered through theterminal P1 from the MPU 14, the DC motor 10 is rotated in the normaldirection, whereby the seatbelt is retracted by the reel shaft 3, whileif a high-level control signal delivered through the terminal P2 fromthe MPU 14, the DC motor 10 is rotated in the reverse direction, wherebythe seatbelt is protracted by the reel shaft 3.

In FIG. 2, reference numeral C1 designates a current detecting circuitwhich detects current i flowing to the DC motor 10, based upon currentflowing through a resistance r1. The current detecting circuit C1 iscomprised of interface circuits (hereinafter abbreviated as “IFs”) IF1and IF2 which operate to remove current fluctuations or variations dueto the influence of the PWM signal. The MPU 14 receives voltage signalsfrom the IFs IF1 and IF2 and detects current i flowing to the DC motor10 from these voltage signals.

In FIG. 2, reference numeral C2 designates a voltage measuring circuit 2which measures terminal voltage across the DC motor 10, and is comprisedof IFs IF3 and IF4 which operate to remove fluctuations or variations inthe terminal voltage due to the influence of the PWM signal. The MPU 14receives voltage signals from the IFs IF3 and IF4 and measures theterminal voltage across the DC motor 10 from these voltage signals.

The IFs IF1 to IF4 are each formed by a low-pass filter formed of aresistance r2, a resistance r3 smaller in resistance value than theresistance r2, and a capacitor c3, all the IFs having a cutoff frequencyof 20 Hz, for example. By virtue of these IFs, the influence of the PWMsignal output from the MPU 14 upon the current detecting circuit C1 andthe voltage measuring circuit C2 is reduced to −60 dB, which is almostnegligible for detection of current by the current detecting circuit C1and detection of terminal voltage by the voltage measuring circuit C2.

Referring back to FIG. 1, the MPU 14 has a built-in timer 21 formeasuring time. Connected to the MPU 14 are a buckle connection detector16 which detects whether a tongue of the seatbelt has been attached toor mounted on the buckle and whether the tongue of the seatbelt has beendisconnected from the buckle, and a temperature sensor 19 which detectstemperature in the vicinity of the DC motor 10 or the temperature of theDC motor 10 itself.

FIG. 3 is a flowchart showing a fault diagnosis program executed by theMPU 14.

First, a flag FLAG, which, when set to 1, indicates that the DC motordriver 11 functions abnormally, and when set to 0, indicates that the DCmotor driver 11 functions normally, is reset to 0 at a step S301.

Then, a high-level signal, for example, a single pulse having arectangular waveform and a pulse width of 0.5 ms is applied to theterminal P1 at a step S302, and the lapse of a predetermined time period(e.g. 0.2 ms) is waited after the application of the high-level signalat a step S303. Then, terminal voltage Va is measured from a value ofcurrent flowing between the terminals P3 and P4 at a step S304, and itis determined at a step S305 whether the measured terminal voltage Vafalls within a range between 4 volts and 6 volts. An example of theterminal voltage between the terminals P3 and P4 is shown in FIG. 4A.

If the measured terminal voltage Va does not fall within the rangebetween 4 volts and 6 volts, the flag FLAG is set to 1 at a step S309,followed by terminating the present processing. If the measured terminalvoltage Va falls within the above range, the lapse of a predeterminedtime period (e.g. 0.4 ms) is waited at a step S306. During the waiting,the flag FLAG is held at 0 to indicate that the DC motor driver 11 isnormal.

Then, terminal voltage Vb is again measured from a value of current thenflowing between the terminals P3 and P4 at a step S307, followed bydetermining at a step S308 whether the measured terminal voltage Vbfalls within a range between 3 volts and 5 volts. If it is determined atthe step S308 that the measured terminal voltage Va does not fall withinthe above range, the flag FLAG is set to 1 at the step S309, followed byterminating the present processing. On the other hand, if it isdetermined that the measured terminal voltage Vb falls within the rangebetween 3 volts and 5 volts, the flag FLAG is held at 0, followed byterminating the present processing.

The MPU 14 notifies the occupant through a display device or a warninglight (not shown) whether the DC motor driver 11 is normal or abnormal,based upon the value of the flag FLAG which indicates results of theabove described fault diagnosis. In the above described manner, the MPU14 can perform fault diagnosis of the DC motor driver 16 includingcharacteristics of the DC motor 10.

Although in the above described fault diagnosis program, the MPU 14applies the high-level signal to the DC motor driver 11 through theinput terminal P1, a similar fault diagnosis program is also executed bythe MPU 14 by applying a high-level signal to the DC motor driver 16through the other input terminal P2.

As described above, according to the first embodiment, after thehigh-level signal, e.g. a single pulse with a pulse width of 0.5 ms isapplied from the MPU to the input terminal P1 to the DC motor driver 11,two kinds of the terminal voltage Va and Vb are measured based uponcurrent flowing between the terminals P3 and P4, to determine, basedupon the measured terminal voltage Va and Vb, whether the DC motordriver 11 is normal or abnormal. As a result, accurate fault diagnosiscan be carried out. Further, based upon the value of the flag FLAG,results of the fault diagnosis are notified to the occupant by means ofa display device or a warning light, whereby the occupant can notice afault of the DC motor driver 11 and take appropriate measures.

Although in the present embodiment the terminal voltage is measuredtwice based upon current flowing between the terminals P3 and P4, theterminal voltage may be measured only once or three times or more. Ifthe number of times of measurement is increased, more accurate faultdiagnosis can be achieved.

Second to thirteenth embodiments of the invention will be describedhereinbelow. In the description of these embodiments, elements and partsas well as steps corresponding to those in the first embodimentdescribed above are designated by identical reference numerals, detaileddescription of which is omitted. In the following, only those whichdiffer from the first embodiment will be described.

Second Embodiment

An automotive passenger restraint and protection apparatus according toa second embodiment of the invention includes an electric retractorwhich is identical in construction with the electric retractor 100 ofthe first embodiment described above, description of which is thereforeomitted. The second embodiment is distinguished from the firstembodiment only in the manner of fault diagnosis executed by the MPU 14.

A manner of fault diagnosis according to the present embodiment,executed by the MPU 14 will be described hereinbelow.

FIG. 5 is a flowchart showing a fault diagnosis program according to thepresent embodiment, executed by the MPU 14.

First, the flag FLAG is reset to 0 at a step S501. Then, a signal of aTTL (Transistor Transistor Level) level having a frequency of 10 kHz anda duty factor of 10%, for example is applied to the terminal P1 at astep S502, and the lapse of a predetermined time period (e.g. 1 sec) iswaited after the application of the TTL level signal at a step S503. Anexample of the waveform of terminal voltage then applied between theterminals P3 and P4 is shown in FIG. 4B.

Then, terminal voltage Vc is measured from a value of current flowingbetween the terminals P3 and P4 at a step S504, followed by stopping theapplication of the TTL level signal to the terminal P1 at a step S505.Then, it is determined at a step S506 whether the measured terminalvoltage Vc falls within a range between 0.5 volts and 2 volts.

If the measured terminal voltage Vc does not fall within the rangebetween 0.5 volts and 2 volts, the flag FLAG is set to 1 at a step S507,followed by terminating the present processing. If the measured terminalvoltage Vc falls within the above range, the flag FLAG is held at 0 toindicate that the DC motor driver 11 is normal, followed by terminatingthe present processing.

The MPU 14 notifies the occupant through a display device or a warninglight (not shown) whether the DC motor driver 11 is normal or abnormal,based upon the value of the flag FLAG which indicates results of theabove described fault diagnosis. In the above described manner, the MPU14 can perform fault diagnosis of the DC motor driver 16 includingcharacteristics of the DC motor 10.

Although in the above described fault diagnosis program, the MPU 14applies the TTL level signal to the DC motor driver 11 through the inputterminal P1, a similar fault diagnosis program is also executed by theMPU 14 by applying a TTL level signal to the DC motor driver 16 throughthe other input terminal P2.

As described above, according to the second embodiment, after theapplication of a TTL level signal having a frequency of 10 kHz and aduty factor of 10%, for example, to the terminal P1, terminal voltage Vcis measured from a value of current flowing between the terminals P3 andP4, to determine whether the measured terminal voltage Vc falls within apredetermined range. Based upon results of the determination, whetherthe DC motor driver 11 is normal or abnormal is determined. As a result,accurate fault diagnosis can be carried out. Further, based upon thevalue of the flag FLAG, results of the fault diagnosis are notified tothe occupant by means of a display device or a warning light, wherebythe occupant can notice a fault of the DC motor driver 11 and takeappropriate measures.

Third Embodiment

An automotive passenger restraint and protection apparatus according toa third embodiment of the invention includes an electric retractor 300which is distinguished from the electric retractor 100 of the firstembodiment only in the construction of the DC motor driver 11. Exceptfor this, the construction of the electric retractor 300 is identicalwith the electric retractor, description of which is therefore omitted.

FIG. 6 is a circuit diagram of the construction of the DC motor driver11 according to the present embodiment.

The construction of the DC motor driver 11 employed in the presentembodiment is distinguished from that of the DC motor driver 11 employedin the first embodiment (FIG. 2) in that the IFs IF3 and IF4 areomitted, and a load 12 for use in the fault diagnosis is connected inparallel with the DC motor 10, and a switch 13 is provided for selectingthe DC motor 10 or the load 12. The load has load characteristicsequivalent to electrical characteristics of the DC motor 10. Except forthese points, the construction of the DC motor driver 11 of the presentembodiment is identical with that shown in FIG. 2, description of whichis therefore omitted.

The switch 13 is adapted to operate in response to a control signal fromthe MPU 14 to be selectively connected to the DC motor 10 side or to theload 12 side.

FIG. 7 is a flowchart showing a fault diagnosis program executed by theMPU 14.

First, the flag FLAG is reset to 0 at a step S701.

Then, the switch 13 is connected to the load 12 side at a step S702, anda high-level signal, for example, a single pulse having a rectangularwavefor and a pulse width of 0.5 ms, is applied to the terminal P1 at astep S703. Then, terminal voltage Va is measured from a value of currentflowing between the terminals P3 and P4 at a step S704, followed byapplying a low-level signal to the terminal P1 at a step S705.

Then, the switch 13 is connected to the DC motor 10 side at a step S706,and then again a high-level signal, for example, a single pulse having arectangular waveform and a pulse width of 0.5 ms, is applied to theterminal P1 at a step S707. Then, terminal voltage Vb is measured basedupon a value of current flowing between the terminals P3 and P4 at astep S708, followed by applying a low-level signal to the terminal P1 ata step S709.

Then, it is determined at a step S710 whether the absolute value of thedifference between the measured terminal voltage Va and the measuredterminal voltage Vb is larger than a predetermined value. Thepredetermined value is set based upon temperature in the vicinity of theDC motor 10 and the load 12 or the temperature of the DC motor 10 andthe load 12 themselves.

If it is determined at the step S710 that the absolute value is notlarger than the predetermined value, the present program is terminatedso that the flag FLAG is held at 0, whereas if the absolute value is notlarger than the predetermined value, the flag FLAG is set to 1 at a stepS711, followed by terminating the present processing.

The MPU 14 notifies the occupant through a display device or a warninglight (not shown) whether the DC motor driver 11 is normal or abnormal,based upon the value of the flag FLAG which indicates results of theabove described fault diagnosis. In the above described manner, the MPU14 can perform fault diagnosis of the DC motor driver 16 includingcharacteristics of the DC motor 10.

Although in the above described fault diagnosis program, the MPU 14applies the high-level signal and low-level signal to the DC motordriver 11 through the input terminal P1, a similar fault diagnosisprogram is also executed by the MPU 14 by applying a high-level signaland a low-level signal to the DC motor driver 16 through the other inputterminal P2.

As described above, according to the third embodiment, terminal voltageVa applied when the load 12 is connected and terminal voltage Vb appliedwhen the DC motor 10 is connected are measured, and based upon whetherthe absolute value of the difference between the measured terminalvoltage Va and the measured terminal voltage Vb, it is determinedwhether the DC motor driver 11 is normal or abnormal. As a result,accurate fault diagnosis can be carried out. Further, results of thefault diagnosis are notified to the occupant by means of a displaydevice or a warning light, whereby the occupant can notice a fault ofthe DC motor driver 11 and take appropriate measures.

Although in the third embodiment, as the high-level signal, a singlepulse having a pulse width of 0.5 ms is applied (steps S703 and S707), apulse train having a frequency of 10 kHz and a duty factor of 10%, forexample, may be applied, instead.

Fourth Embodiment

An automotive passenger restraint and protection apparatus according toa fourth embodiment of the invention includes an electric retractor 400which is distinguished from the electric retractor 100 of FIG. 1 in thata warning device is connected to the MPU 14 for giving warning by meansof a warning buzzer, a warning light or the like, in place of thetemperature sensor 19 shown in FIG. 1, and except for this, theconstruction of the electric retractor 400 is identical with that ofFIG. 1, illustration and description of which are therefore omitted.

FIG. 8 is a flowchart showing a fault diagnosis program according to thefourth embodiment, executed by the MPU 14. This program is stored in amemory, not shown, within the MPU 14 and executed at predetermined timeintervals t1 (e.g. 15 sec).

First, terminal voltage V across the DC motor 10 is measured by thevoltage detecting circuit C2 and at the same time the timer 15 isstarted to measure elapsed time at a step S801.

Then, it is determined at a step S802 whether the measured terminalvoltage V has continuously fallen within a range between a firstpredetermined value V1 (e.g. 5 volts) and a second predetermined valueV2 (e.g. 10 volts) over a predetermined time period t2 (e.g. 10 sec).The first and second predetermined values V1 and V2 are both higher thana range assumed when the DC motor 10 and the DC motor driver 11 arefunctioning normally, but are set to values defining a range to beassumed when the DC motor 10 runs idle due to abnormality of the powertransmission mechanism or the like and the DC motor 10 and the DC motordriver 11 are not truly faulty. In the following description, the term“fault” indicates a state where the DC motor 10 runs idle due toabnormality of the power transmission mechanism or the like. If themeasured terminal voltage V has not continuously fallen within the rangebetween the first predetermined value V1 and the second predeterminedvalue V2 over the predetermined time period t2, it is determined thatthere is no “fault”, and then the present program is immediatelyterminated, whereas if the measured terminal voltage V has continuouslyfallen within the range between the first predetermined value V1 and thesecond predetermined value V2 over the predetermined time period t2, itis determined that there is a “fault”, and then a PWM signal isdelivered from the MPU 14 to the DC motor driver 11 to stop the drivingof the DC motor 10 at a step S803, and a control signal is deliveredfrom the MPU 14 to the warning device to give warning by the warningbuzzer, the warning light or the like at a step S804, followed byterminating the present processing.

FIG. 9 is a flowchart showing another fault diagnosis program accordingto the present embodiment. This program is stored in a memory, notshown, within the MPU 14 and executed at predetermined time intervals t1(e.g. 15 sec).

First, current i flowing to the DC motor 10 is measured by the currentdetecting circuit C1 and at the same time the timer 15 is started tomeasure elapsed time at a step S901.

Then, it is determined at a step S902 whether the measured current i hascontinuously fallen within a range between a first predetermined valuei1 (e.g. 2 amperes) and a second predetermined value i2 (e.g. 4 amperes)over a predetermined time period t3 (e.g. 10 sec). The first and secondpredetermined values i1 and i2 are both larger than a range assumed whenthe DC motor 10 and the DC motor driver 11 are functioning normally, butare set to values defining a range to be assumed when the DC motor 10runs idle due to abnormality of the power transmission mechanism or thelike and the DC motor 10 and the DC motor driver 11 are not trulyfaulty. In the following description, the term “fault” indicates a statewhere the DC motor 10 runs idle due to abnormality of the powertransmission mechanism or the like. If the measured current i has notcontinuously fallen within the range between the first predeterminedvalue i1 and the second predetermined value i2 over the predeterminedtime period t3, it is determined that there is no “fault”, and then thepresent program is immediately terminated, whereas if the measuredcurrent i has continuously fallen within the range between the firstpredetermined value i1 and the second predetermined value i2 over thepredetermined time period t3, it is determined that there is a “fault”,and then the processing proceeds to a step S903. The step S903 and astep S904 are identical with the above described steps S803 and S804 ofFIG. 8, description of which is therefore omitted.

As described above, according to the present embodiment, if the terminalvoltage V has continued to fall within the range between the first andsecond predetermined values V1 and V2 to be assumed when the DC motor 10runs idle due to abnormality of the power transmission mechanism or thelike, over the predetermined time period t2, or if the current i hascontinued to fall within the range between the first and secondpredetermined values i1 and i2 to be assumed when the DC motor 10 runsidle due to abnormality of the power transmission mechanism or the like,over the predetermined time period t3, it is determined that there is a“fault”, that is, the DC motor 10 has been running idle for aconsiderable time period so that the DC motor 10 or the DC motor driver11 can subsequently become truly faulty, and a warning is given by thewarning device. As a result, accurate fault diagnosis can be achievedand the detected fault can be notified to the occupant.

As a variation of the present embodiment, the determination of the stepS802 of FIG. 8 and that of the step S902 of FIG. 9 may be combinedtogether to carry out both of these determinations. For example, it maybe determined that there is a “fault” if the measured terminal voltage Vhas continuously fallen within the range between the first predeterminedvalue V1 and the second predetermined value V2 over the predeterminedtime period t2 and at the same time the measured current i hascontinuously fallen within the range between the first predeterminedvalue i1 and the second predetermined value i2 over the predeterminedtime period t3.

Fifth Embodiment

An electric retractor 500 provided in an automotive passenger restraintand protection apparatus according to a fifth embodiment of theinvention is distinguished from the electric retractor of FIG. 1 in thata torque sensor 4, a tension sensor 9, and a warning device 7 areadditionally provided.

The electric retractor 500 according to the fifth embodiment will now bedescribed with reference to FIG. 10 showing the arrangement of the same.

As shown in FIG. 10, the electric retractor 500 includes the torquesensor 4, the tension sensor 9, the warning device 17, the buckleconnection detector 16, and the temperature sensor 19, which areconnected to the MPU 14.

The warning device 17 is for giving warning when an abnormality of theDC motor 10 is detected by the MPU 14 in a manner described hereinafter.

The tension sensor 9 senses tension α of the seatbelt 8 and delivers asignal indicative of the sensed tension α to the MPU 14. The torquesensor 4 senses rotational torque β of the reel shaft 3 and delivers asignal indicative of the sensed rotational torque β to the MPU 14.

The construction of the DC motor driver 11 employed in the fifthembodiment is identical with that shown in FIG. 1, except that a switchis provided between the battery Vb and the DC motor 10, for selectivelyconnecting or disconnecting the former to or from the latter to supplyof the supply voltage to the DC motor 10 or stop the supply.Illustration of the construction of the DC motor driver 11 is thereforeomitted.

FIG. 11 is a flowchart showing a main status control program accordingto the fifth embodiment, executed by the MPU 14. This control program isexecuted every predetermined time period.

First, status control is executed based upon results of a determinationof the current i flowing to the DC motor 10 at a step S1201. Details ofthe status control will be described with reference to FIG. 12. Upon thestart of the status control at the step S1201, the timer 15 startsmeasuring time t elapsed after the start of execution of the statuscontrol program at the step S1201.

Then, status control is executed based upon results of the detection ofthe tension α of the seatbelt 8 by the tension sensor 9 at a step S1202.Details of the status control at the step S1202 will be described withreference to FIG. 13. Upon the start of the status control at the stepS1202, the timer 15 starts measuring time t elapsed after the start ofexecution of the status control program at the step S1202.

Then, status control is executed based upon results of the detection ofthe rotational torque β of the reel shaft 3 by the torque sensor 4 at astep S1203. Details of the status control at the step S1203 will bedescribed with reference to FIG. 14. Upon the start of the statuscontrol at the step S1203, the timer 15 starts measuring time t elapsedafter the start of execution of the status control program at the stepS1203.

Lastly, status control is executed based upon results of the temperatureγ of the temperature in the vicinity of the DC motor 10 or thetemperature of the DC motor 10 itself at a step S1204, followed by theprogram returning to the step S1201. Details of the status control atthe step S1204 will be described with reference to FIG. 15. Upon thestart of the status control at the step S1204, the timer 15 startsmeasuring time t elapsed after the start of execution of the statuscontrol program at the step S1204.

FIG. 12 is a flowchart showing the status control program executed atthe step S1201.

First, the current i flowing to the DC motor 10 is detected by thecurrent detecting circuit C1 at a step S1301, and it is determinedwhether the detected current i exceeds a predetermined value (e.g. 1.4amperes). If the current i does not exceed the predetermined value, itis determined that the DC motor 10 is functioning normally, and then thetime t measured by the timer 15′ after the start of the present statuscontrol program is reset to 0 at a step S1304, followed by terminatingthe present processing. On the other hand, if the detected current iexceeds the predetermined value, the value of the timer 15 isincremented by 1 at a step S1303.

Then, it is determined at a step S1305 whether the elapsed time texceeds a predetermined time period t (e.g. 60 sec). If the former doesnot exceed the latter, it is determined that the DC motor 10 isfunctioning normally, and the present program is immediately terminated,whereas if the former exceeds the latter, it is determined that the DCmotor 10 is abnormal, and then the switch 35 of the DC motor driver 11is operated to stop the supply of the supply voltage from the battery Vbto the DC motor 10 at a step S1306, followed by terminating the presentprocessing.

According to the above status control program (step S1201), if thecurrent i flowing to the DC motor 10 has continued to exceed thepredetermined value (1.4 amperes) over the predetermined time period (60sec), it is determined that the DC motor 10 is abnormal, and then thesupply of the supply voltage from the battery Vb to the DC motor 10 isstopped. Therefore, it is possible to prevent the DC motor 10 frombecoming faulty.

FIG. 13 is a flowchart showing the status control program executed atthe step S1202.

First, the tension α of the seatbelt 8 is sensed by the tension sensor 9at a step S1401, and it is determined at a step S1402 whether the sensedtension α is larger than a predetermined value (e.g. 12 mN). If thesensed tension α is not larger than the predetermined value, it isdetermined that the DC motor 10 is functioning normally, and then theprocessing proceeds to a step S1404. On the other hand, if the sensedtension α is larger than the predetermined value, the processingproceeds to a step S1403. The steps S1403 to S1406 are identical withthe steps S1303 to S1306 of FIG. 12 described above, description ofwhich is therefore omitted.

According to the above status control program (step S1202), if thesensed tension α has continued to be larger than the predetermined value(12 mN) over the predetermined time period (60 sec), it is determinedthat the DC motor 10 is abnormal, and then the supply of the supplyvoltage from the battery Vb to the DC motor 10 is stopped. Therefore, itis possible to prevent the DC motor 10 from becoming faulty.

FIG. 14 is a flowchart showing the status control program executed atthe step S1203.

First, the rotational torque β of the reel shaft 3 is sensed by thetorque sensor 4 at a step S1501, and it is determined at a step S1502whether the sensed rotational torque β is larger than a predeterminedvalue (e.g. 30 mN.cm). If the sensed rotational torque β is not largerthan the predetermined value, it is determined that the DC motor 10 isnormal, and then the processing proceeds to a step S1504, whereas if thesensed rotational torque β is larger than the predetermined value, theprocessing proceeds to a step S1503. The steps S1503 to S1506 areidentical with the steps S1303 to S1306 of FIG. 12 described above,description of which is therefore omitted.

According to the above status control program (step S1203), if thesensed rotational torque β has continued to be larger than thepredetermined value (30 mN.cm) over the predetermined time period (60sec), it is determined that the DC motor 10 is abnormal, and then thesupply of the supply voltage from the battery Vb to the DC motor 10 isstopped. Therefore, it is possible to prevent the DC motor 10 frombecoming faulty.

FIG. 15 is a flowchart showing the status control program executed atthe step S1204.

First, the temperature γ in the vicinity of the DC motor 10 or thetemperature of the DC motor 10 itself is sensed by the temperaturesensor 19 at a step S1601, and it is determined at a step S1602 whetherthe sensed temperature γ exceeds a predetermined value (e.g. 100° C.).If the sensed temperature γ does not exceed the predetermined value, itis determined that the DC motor 10 is normal, and then the processingproceeds to a step S1604, whereas if the sensed temperature γ exceedsthe predetermined value, the processing proceeds to a step S1603. Thesteps S1603 to S1606 are identical with the steps S1303 to S1306 of FIG.12 described above, description of which is therefore omitted.

According to the above status control program (step S1204), if thesensed temperature γ has continued to exceed the predetermined value(100° C.) over the predetermined time period (60 sec), it is determinedthat the DC motor 10 is abnormal, and then the supply of the supplyvoltage from the battery Vb to the DC motor 10 is stopped. Therefore, itis possible to prevent the DC motor 10 from becoming faulty.

Although in the above described steps S1306, S1406, S1506, and S1606,when it is determined that the DC motor 10 is abnormal, and the supplyof the supply voltage to the DC motor 10 is stopped by means of theswitch, alternatively a transformer or the like may be provided and thesupply voltage from the battery Vb to the DC motor 10 may be decreasedby the transformer or the like.

Further, in addition to stopping the supply of the supply voltage to theDC motor 10 or decreasing the supply voltage, the warning device 17 maybe actuated to give warning to notify the occupant of the abnormal stateof the DC motor 10.

Further alternatively, a control signal in the form of a pulse signalmay be delivered from the MPU 14 through the terminal P1 in FIG. 2 tothe DC motor driver 11, and if it is determined that the DC motor 10 isabnormal, the pulse width, i.e. duty factor of the pulse signal may bevaried. More specifically, the duty factor of the pulse signal isdecreased. This provides substantially the same results as decreasingthe supply voltage to the DC motor 10.

Furthermore, a high-level signal may be delivered as the control signalfrom the MPU 14 through the terminal P2 in FIG. 2 to the DC motor driver11 when it is determined that the DC motor 10 is normal, and when it isdetermined that the DC motor 10 is abnormal, and a low-level signal maybe delivered from the MPU 14 through the terminal P2 to the DC motordriver 11 when it is determined that the DC motor 10 is abnormal. Thiscauses a decrease in the current flowing to the DC motor 10, providingsubstantially the same results as decreasing the supply voltage to theDC motor 10.

The parameters used for the abnormality determination, i.e. current i,tension α, rotational torque β, and temperature γ are merelyillustrative and not limitative.

Sixth Embodiment

FIG. 16 shows the construction of an electric retractor 600 provided inan automotive passenger restraint and protection apparatus according toa sixth embodiment of the invention, which is distinguished from theelectric retractor 100 of FIG. 1 only in that a winding amount detector37, a warning device 38, a collision predictor 41, and a vehicle sensor42, which are connected to the MPU 14, in place of the temperaturesensor 19.

The following description relates to these component elements 16, 37,38, 41, and 42 and the MPU. The construction of the other componentelements is identical with that of those of the electric retractor 100,description of which is therefore omitted.

The MPU 14 has built-in timers 15, 39 and 40 for measuring elapsed time.The winding amount detector 37 detects an amount of winding of theseatbelt, i.e. an amount of winding of the seatbelt on the reel shaft 3.The collision predictor 41 detects whether there is a fear of acollision of the automotive vehicle or a collision of the automotivevehicle is unavoidable. The vehicle speed sensor 42 senses the travelingspeed of the automotive vehicle.

The MPU 14 has a memory, not shown, which stores programs such ascontrol programs, and a vibration flag used to cause vibration of theseatbelt by alternately protracting and retracting the seatbelt throughexecution of programs.

The buckle connection detector 16 detects whether the tongue of theseatbelt has been attached to or disconnected from the buckle, anddelivers an ON signal when it detects that the seatbelt tongue has beenattached to the buckle, and an OFF signal when it detects that theseatbelt tongue has been disconnected from the buckle.

The winding amount detector 37 does not detect a specific value of thewinding amount, but determines whether the thickness of a portion of theseatbelt wound on the reel shaft 3 exceeds a predetermined value. Itdelivers an ON signal to the MPU 14 when the thickness exceeds thepredetermined value, whereas it delivers an OFF signal to the MPU 14when the thickness does not exceed the predetermined value. Thepredetermined value is set to a value intermediate between an amount ofwinding or retraction to be assumed when the seatbelt is in a stored orfully retracted state and an amount of winding or retraction to beassumed when the seatbelt is in a state attached to the occupant.

FIG. 17 is a view showing an example of the waveforms of signals inputto the MPU 14 when the buckle connection detector 16 is normal.

At a time point when the occupant starts protracting the seatbelt inorder to mount the seatbelt onto his body, the ON signal from thewinding amount detector 37 has already been delivered to the MPU 14 andalso the OFF signal from the buckle connection detector 16 has alreadybeen delivered to the MPU 14. If the occupant then further protracts theseatbelt so that the winding amount decreases below the predeterminedvalue, the winding amount detector 37 starts delivering the OFF signal.Thereafter, when the seatbelt has become attached to the occupant, thatis, the seatbelt has been attached to the buckle, the buckle connectiondetector 16 starts delivering the ON signal. At this time, the windingamount detector 37 continues delivering the OFF signal.

Subsequently, when the seatbelt is disconnected from the occupant, thatis, the seatbelt tongue is disconnected from the buckle, the signalreceived from the buckle connection detector 16 changes from the ONsignal to the OFF signal. At this time, the MPU 14 starts seatbeltstoring control to start retracting the seatbelt. When the windingamount of the seatbelt increases above the predetermined value, thesignal received from the winding amount detector 37 changes from the OFFsignal to the ON signal.

FIG. 18 is a flowchart showing the seatbelt storing control.

First, the MPU 14 delivers a PWM signal to the DC motor driver 11 tothereby rotate the DC motor 10 in the seatbelt retracting direction at astep S1901. It is then determined at a step S1902 whether the retractionof the seatbelt has reached its limit, base upon the current flowing tothe DC motor 10. If the retraction of the seatbelt has not reached itslimit, that is, the seatbelt can still be retracted by the DC motor 10,the processing returns to the step S1901, whereas if the retraction ofthe seatbelt has reached its limit, the present processing isterminated. The expression “the retraction of the seatbelt has reachedits limit” means that the DC motor 10 ceases to rotate in the seatbeltretracting direction.

Now, description will be made of processing executed by the MPU 14 inthe event that the buckle connection detector 16 continues deliveringthe ON signal even when the seatbelt is in a state disconnected from thebuckle (hereinafter referred to as “ON fault”).

FIG. 19 shows an example of the waveforms of signals input to the MPU 14when “ON fault” occurs with the seatbelt disconnected from the occupant.FIGS. 20 and 21 are flowcharts showing a control program executed by theMPU 14. This control program is started when the ON signal is deliveredfrom the winding amount detector 37 to the MPU 14 and at the same timethe ON signal is delivered from the buckle connection detector 16 to theMPU 14.

First, a counter n for use in the present control program is reset to 0and a seatbelt storage flag is reset at a step S2101. It is thendetermined at a step S2102 whether the seatbelt is being protracted,from the terminal voltage across the DC motor 10. If the seatbelt is notbeing protracted, the same determination is repeated, whereas if theseatbelt is being protracted, it is determined at a step S2103 whetherthe signal received from the winding amount detector 37 has changed fromthe ON signal to the OFF signal. If no change has occurred in thereceived signal, it is determined at a step S2104 whether theprotraction of the seatbelt has been terminated, from the terminalvoltage across the DC motor 10.

If the protraction of the seatbelt has not been terminated, theprocessing returns to the step S2103, whereas if the protraction of theseatbelt has been terminated, the processing proceeds to a step S2132 toexecute seatbelt storing control, described hereinafter. If it isdetermined at the step S2103 that the signal received from the windingamount detector 37 has changed from the ON signal to the OFF signal, itis determined at a step S2105 whether the signal received from thebuckle connection detector 16 is the ON signal. If it is the OFF signal,it is determined that there is no ON fault, and then, after the lapse ofa predetermined time period t1, it is determined at a step S2106 whetherthe signal received from the buckle connection detector 16 is the ONsignal.

If the signal from the buckle connection detector 16 is the OFF signal,the timer 15 is started at a step S2112, and then it is determined at astep S2113 whether the seatbelt has been protracted, from the terminalvoltage across the DC motor 10. If the seatbelt has been protracted, thetimer 15 is stopped and cleared at a step S2114, and the seatbeltstorage flag is set at a step S2115, followed by the processingreturning to the step S2102. On the other hand, if the seatbelt has notbeen protracted, it is determined at a step S2116 whether apredetermined time period t2 (e.g. 4 sec) has elapsed, from the value ofthe timer 15. If the predetermined time period t2 has not elapsed, theprocessing returns to the step S2113, whereas if the predetermined timeperiod t2 has elapsed, the timer 15 is stopped and cleared at a stepS2117, and it is determined at a step S2118 whether the seatbelt storageflag has been set.

If the seatbelt storage flag has been set, the same flag is reset at astep S2119, and then the seatbelt storing control of FIG. 18 is executedat a step S2120, followed by the processing returning to the step S2102.

If it is determined at the step S2118 that the seatbelt storage flag hasnot been set, it is determined at a step S2121 whether the count valueof the counter n has reached a predetermined value (e.g. 5). If thecount value has reached the predetermined value, the processing returnsto the step S2102, whereas if the count value has not reached thepredetermined value, the seatbelt storing control is executed at a stepS2122, similarly to the step S2120. After completion of the seatbeltstoring control, the count value of the counter n is incremented by 1 ata step S2123, followed by the processing returning to the step S2102.

If it is determined at the step S2106 that attaching of the seatbelt tothe buckle has been detected from the signal from the buckle connectiondetector 16, a timer interrupt triggered in response to the value of thetimer 22 is made effective at a step S2107, whereby timer interruptprocessing is executed at predetermined time intervals (e.g. 0.1 sec),as described hereinbelow.

FIG. 22 is a flowchart showing the timer interrupt processing.

First, upon the start of execution of the timer interrupt processing,the timer interrupt is made ineffective at a step S2301. Then, it isdetermined at a step S2302 whether attaching of the seatbelt tongue tothe buckle has been detected by the buckle connection detector 16. Ifattaching of the seatbelt has not been detected, the counter n is resetto 0 and the seatbelt storage flag is reset at a step S2303, and thenthe program jumps to a step S2304 to execute the seatbelt storingcontrol of the step S2120.

On the other hand, if it is determined at the step S2302 that attachingof the seatbelt has been detected, it is determined at a step S2305whether an output signal from the collision predictor 41 has beenreceived, which indicates that a collision of the vehicle isunavoidable. If the output signal has been received, a PWM signal isdelivered to the DC motor driver 11 over a predetermined time period t3(e.g. 4 sec) which is measured by the timer 40, to rotate the DC motor10 in the seatbelt retracting direction at a step S2306. Thus, theoccupant can be properly protected in the event of a collision of thevehicle. Then, the timer interrupt is made effective at a step S2307,and the processing proceeds to the step S2108 (step S2308).

If it is determined at the step S2305 that the output signal indicativeof a collision of the vehicle being unavoidable has not been received,it is determined at a step S2309 whether an output signal from thecollision predictor 41 has been received, which indicates that there isa fear of a collision of the vehicle. If the output signal has beenreceived, a PWM signal is delivered to the DC motor driver 11 to rotatethe DC motor 10 alternately in the seatbelt protracting direction and inthe seatbelt retracting direction to vibrate the seatbelt, and thevibration flag is set at a step S2310. The frequency of the vibrationvaries from 1 Hz to 10 kHz so as to provide a vibration which theoccupant can easily feel as a warning. Then, the processing returns tothe step S2305 while the vibration is continued.

If it is determined at the step S2309 that the output signal indicativeof the fear of a collision of the vehicle has not been received, it isdetermined at a step S2311 whether the seatbelt has been being vibrated,from the state of the vibration flag. If the seatbelt has been beingvibrated, the vibration flag is reset and the vibration is stopped at astep S2312, and then the processing proceeds to the step S2307. If theseatbelt has not been being vibrated, the timer interrupt is madeeffective at a step S2313, and then the program return to a step wherethe timer interrupt was input.

Referring back to FIG. 21, the processing then proceeds to the stepS2308 to execute seatbelt slackening control to give a proper amount oflooseness to the occupant so as not to give him a feeling of oppression.

FIG. 23 is a flowchart of the seatbelt slackening control.

First, a PWM signal is delivered from the MPU 14 to the DC motor driver11 to rotate the DC motor 10 in the seatbelt retracting direction at astep S2401, and it is determined at a step S2402 whether the retractionof the seatbelt has reached its limit, based upon the current flowing tothe DC motor 10. When the retraction of the seatbelt has reached itslimit, an improper amount of looseness of the seatbelt can be oncecompletely removed.

If it is determined at the step S2402 that the retraction of theseatbelt has not reached its limit, the processing returns to the stepS2401, whereas if it has reached the limit, a PWM signal is deliveredfrom the MPU 14 to the DC motor driver 11 to rotate the DC motor in theseatbelt protracting direction at a step S2403, and it is determined ata step S2404 whether a predetermined time period t4 (e.g. 1 sec) haselapsed after the protraction of the seatbelt by the DC motor 10 wasstarted. When the predetermined time period t4 has elapsed, a properamount of looseness is given to the occupant.

If it is determined at the step S2404 that the predetermined time periodt4 has not elapsed, the processing returns to the step S2403, whereas ifthe predetermined time period t4 has elapsed, the protraction of theseatbelt by the DC motor 10 is stopped at a step S2405, followed byterminating the present processing.

Referring again to FIG. 21, it is determined at a step S2109 whetherprotraction of the seatbelt has been made, based upon the terminalvoltage across the DC motor 10. If protraction of the seatbelt has notbeen made, the same determination is repeated, whereas if protraction ofthe seatbelt has been made, it is determined at a step S2110 whether theprotraction of the seatbelt has been completed, by determining whetherthe terminal voltage across the DC motor 10 is equal to or less than apredetermined value (e.g. 0.3 volts). If the protraction of the seatbelthas not been completed, the same determination is repeated, whereas ifit has been completed, it is determined at a step S2111 whether thevehicle speed v exceeds a predetermined value v1 (e.g. 10 km/h), basedupon an output signal from the vehicle speed sensor 42.

If the vehicle speed v does not exceed the predetermined value v1, thesame determination is repeated, whereas if the former exceeds thelatter, the processing returns to the step S2108 to again execute theseatbelt slackening control. By virtue of this control, when the vehicleis reversed at a slow speed for parking, for example, the reel shaft isnot normally rotated, it can be prevented that the seatbelt is retractedto its limit while the occupant looks backward.

Referring back to FIG. 20, if it is determined at the step S2105 thatthe signal received from the buckle connection detector 16 is the ONsignal, the MPU 14 judges that the buckle connection detector 16 has theON fault, and then causes the warning device 38 to give warning at astep S2124.

Then, it is determined at a step S2125 whether a predetermined timeperiod t5 (e.g. 10 sec) has elapsed. If the predetermined time period t5has not yet elapsed, the same determination is repeated, whereas if thepredetermined time period t5 has elapsed, it is determined at a stepS2126 whether the signal received from the winding amount detector 37 isstill the OFF signal. If the signal from the winding amount detector 37has changed to the ON signal, the processing proceeds to the seatbeltstoring control at a step S2132, whereas if the signal from the windingamount detector 37 is still the OFF signal, it is regarded that theseatbelt has been attached to the occupant, and then the processingproceeds to a step S2127 to execute seatbelt slackening control of FIG.23.

Then, it is determined at a step S2128 whether the seatbelt has beenprotracted by the occupant, from the terminal voltage across the DCmotor 10. If the seatbelt has been protracted by the occupant, it isdetermined at a step S2129 whether the protraction of the seatbelt hasbeen terminated, from the terminal voltage. If the protraction has beenterminated, the seatbelt slackening control is again executed at thestep S2127.

If it is determined at the step S2128 that the seatbelt has not beenprotracted by the occupant, the seatbelt is forcibly retracted everypredetermined time period t6 (e.g. 5 sec) so long as the signal receivedfrom the winding amount detector 37 is the OFF signal, and it isdetermined at a step S2131 whether the signal from the winding amountdetector 37 has changed from the OFF signal to the ON signal before theretraction of the seatbelt has reached its limit.

If the signal received from the winding amount detector 37 remains to bethe OFF signal, the processing returns to the step S2127, whereas if ithas changed to the ON signal, it is regarded that the seatbelt has beenreleased from the attached state, and then the MPU 14 executes theseatbelt storing control at the step S2132.

As described above, according to the present embodiment, after it isregarded that the buckle connection detector 16 has the ON fault withthe seatbelt disconnected from the occupant, the MPU 14 executes theseatbelt slackening control if the signal received from the windingamount detector 37 is still the OFF signal. As a result, even in thecase where attachment or disconnection of the seatbelt cannot beaccurately detected due to the fault of the buckle connection detector16, a comfortable seatbelt attaching feeling can be given to theoccupant. On the other hand, after it is regarded that the buckleconnection detector 16 has ON fault, if the signal received from thewinding amount detector 37 has changed from the OFF signal to the ONsignal, the seatbelt storing control is executed. As a result, it can beprevented that the seatbelt is caught in the door.

FIG. 24 shows an example of the waveforms of signals input to the MPU 14when “ON fault” occurs after the seatbelt shifts from a state attachedto the occupant to a state disconnected from the occupant. FIGS. 25 and26 are flowcharts showing a control program executed by the MPU 14.

First, the counter n is set to 0 and the seatbelt storage flag is resetat a step S2600, and it is determined at a step S2601 whether the signalreceived from the buckle connection detector 16 is the ON signal. Thestep S2601 and steps S2602 to S2618 are identical with the steps S2106to S2123 of FIG. 21 described above, description of which is omitted.

After the execution of the step S2610, after the answer to the questionof the step S2616 is YES, or after the execution of the step S2615 orS2618, when the seatbelt has shifted from the attached state to thedisconnected state, it is determined at a step S2619 whether the signalreceived from the buckle connection detector 16 has changed from the ONsignal to the OFF signal. If the signal from the buckle connectiondetector 16 remains to be the ON signal, the processing returns to thestep S2601, whereas if the signal from the buckle connection detector 16has changed from the ON signal to the OFF signal, the seatbelt storingcontrol of FIG. 18 is started at a step S2620.

Then, during the execution of the seatbelt storing control, it isdetermined at a step S2621 whether the signal received from the buckleconnection detector 16 has changed from the OFF signal to the ON signal.If there has been no change in the signal, the processing proceeds to astep S2625, hereinafter referred to, whereas if the signal has changedfrom the OFF signal to the ON signal, it is regarded that the seatbelthas shifted from the disconnected state to the attached state, and thenthe seatbelt slackening control of FIG. 23 is started at a step S2622.

While the seatbelt is retracted during the execution of the seatbeltslackening control, it is determined at a step S2623 whether the signalfrom the winding amount detector 37 has changed to the ON signal. If thesignal has not changed to the ON signal, the processing returns to thestep S2622, whereas if it has changed to the ON signal, the MPU 14regards that the buckle connection detector 16 has ON fault, then causesthe warning device 38 to give warning at a step S2624, and againexecutes the seatbelt storing control at a step S2625, followed by theprocessing returning to the step S2601.

As described above, according to the present embodiment, after theseatbelt shifted from the attached state to the disconnected state andthen the MPU 14 regards that the buckle connection detector 16 has ONfault, the seatbelt storing control is executed. As a result, it can beprevented that the seatbelt is caught in the door.

Now, description will be made of processing executed by the MPU 14 inthe event that the buckle connection detector 16 continues deliveringthe OFF signal even when the seatbelt is in a state attached to thebuckle (hereinafter referred to as “OFF fault”).

FIG. 27 is a view showing an example of the waveforms of signals inputto the MPU 14 when “OFF fault” occurs with the seatbelt disconnectedfrom the occupant. FIG. 28 is a flowchart showing a control programexecuted by the MPU 14.

The present control program is started when the ON signal from thewinding amount detector 37 and at the same time the OFF signal from thebuckle connection detector 16 are received by the MPU 14.

First, the counter n is set to 0 and the seatbelt storage flag is resetat a step S2901, and it is determined at a step S2902 whether theseatbelt is being protracted, from the terminal voltage across the DCmotor 10. If the seatbelt is not being protracted, the samedetermination is repeated, whereas if the seatbelt is being protracted,it is determined at a step S2903 whether the signal received from thewinding amount detector 37 has changed from the ON signal to the OFFsignal. If there has been no change in the signal, it is determined at astep S2904 whether the protraction of the seatbelt has been terminated,from the terminal voltage across the DC motor 10.

If the protraction of the seatbelt has not been terminated, theprocessing returns to the step S2903, whereas if the protraction hasbeen terminated, the processing proceeds to a step S2911 to execute theseatbelt storing control, described hereinafter.

If it is determined at the step S2903 that the signal from the windingamount detector 37 has changed from the ON signal to the OFF signal, itis determined at a step S2905 whether a predetermined time period t7(e.g. 10 sec) has elapsed while the OFF signal continues to be receivedfrom the winding amount detector 37.

If the predetermined time period t7 has not yet elapsed, the samedetermination is repeated, whereas if it has elapsed, it is determinedat a step S2906 whether the signal from the buckle connection detector16 is the OFF signal.

If the signal from the buckle connection detector 16 is the ON signal,the processing proceeds to the step S2106 of FIG. 21, whereas if thesignal is the OFF signal, the MPU 14 regards that the buckle connectiondetector 16 has OFF fault, causes the warning device 38 to give warningat a step S2907, and executes the seatbelt slackening control of FIG. 23at a step S2908.

So long as the signal received from the winding amount detector 37 isthe OFF signal, the seatbelt is forcibly retracted every predeterminedtime period t8 (e.g. 5 sec) at a step S2909, and it is determined at astep S2910 whether the signal from the winding amount detector 37 haschanged from the OFF signal to the ON signal before the retraction ofthe seatbelt reaches its limit. If the signal has not changed from theOFF signal to the ON signal, the same determination is repeated, whereasif the signal has changed to the ON signal, the MPU 14 regards that theseatbelt has been released from the attached state, and then executesthe seatbelt storing control of FIG. 18 at the step S2911, followed bythe processing returning to the step S2902.

As described above, according to the present embodiment, after it isregarded that the buckle connection detector 16 has the OFF fault withthe seatbelt disconnected from the occupant, the MPU 14 executes theseatbelt slackening control. As a result, even in the case whereattachment or disconnection of the seatbelt cannot be accuratelydetected due to the fault of the buckle connection detector 16, acomfortable seatbelt attaching feeling can be given to the occupant. Onthe other hand, after it is regarded that the buckle connection detector16 has OFF fault, if the signal received from the winding amountdetector 37 has changed from the OFF signal to the ON signal, theseatbelt storing control is executed. As a result, it can be preventedthat the seatbelt is caught in the door.

FIG. 29 shows an example of the waveforms of signals input to the MPU 14when “OFF fault” occurs after the seatbelt shifts from a state attachedto the occupant to a state disconnected from the occupant. FIG. 30 is aflowchart showing a control program executed by the MPU 14.

The present control program is interrupt processing triggered at regulartime intervals and started when the OFF signal from the winding amountdetector 37 and at the same time the ON signal from the buckleconnection detector 16 are received by the MPU 14.

First, it is determined at a step S3101 whether the signal received fromthe buckle connection detector 16 has changed from the ON signal to theOFF signal. If the signal has not changed from the ON signal to the OFFsignal, the present processing is immediately terminated, whereas if thesignal has changed from the ON signal to the OFF signal, the MPU 14regards that the seatbelt has shifted from the attached state to thedisconnected state, and then executes the seatbelt storing control ofFIG. 18 at a step S3102.

Then, it is determined at a step S3103 whether the signal from thewinding amount detector 37 has changed from the OFF signal to the ONsignal before completion of storing of the seatbelt. If the signal haschanged from the OFF signal to the ON signal, the present processing isterminated, whereas if there has been no change in the signal, that is,the signal from the winding amount detector 37 is still the OFF signaleven when the storing of the seatbelt is just about to be completed, theMPU 14 regards that the buckle connection detector 16 has OFF fault,then causes the warning device 38 to give warning at a step S3104, andexecutes the seatbelt slackening control of FIG. 23 at a step S3105,supposing that the seatbelt is in the attached state.

Then, it is determined at a step S3106 whether the seatbelt has beenprotracted by the occupant, from the terminal voltage across the DCmotor 10. If the seatbelt has been protracted by the occupant, it isdetermined at a step S3107 whether the protraction of the seatbelt hasbeen terminated, from the terminal voltage across the DC motor 10. Ifthe protraction of the seatbelt has been terminated, the seatbeltslackening control is again executed at the step S3105.

If it is determined at the step S3106 that no protraction of theseatbelt has been made by the occupant, so long as the signal receivedfrom the winding amount detector 37 is the OFF signal, the seatbelt isforcibly retracted every predetermined time period t9 (e.g. 5 sec) at astep S3108, and it is determined at a step S3109 whether the signal fromthe winding amount detector 37 has changed from the OFF signal to the ONsignal before the retraction of the seatbelt reaches its limit.

If there has been no change in the signal, the processing returns to thestep S3105, whereas if a change has been made from the OFF signal to theON signal, the present processing is terminated.

As described above, according to the present embodiment, after theseatbelt has shifted from the attached state to the disconnected stateand then it is determined that the buckle connection detector 16 has OFFfault, the seatbelt slackening control is carried out. As a result, evenin the case where attachment or disconnection of the seatbelt cannot beaccurately detected due to the fault of the buckle connection detector16, a comfortable seatbelt attaching feeling can be given to theoccupant.

Although in the present embodiment the winding amount detector 37detects the thickness of the seatbelt wound on the reel shaft 3 as thewinding amount of the seatbelt, the terminal voltage across the DC motor10 or the current flowing to the DC motor 10 may alternatively bedetected to determine the winding amount. That is, when the DC motor 10is not driven, voltage is developed between terminals of the DC motor 10due to an electromotive force thereof, and the voltage is detected andaccumulated, to determine the amount of retraction or protraction of theseatbelt from the resulting cumulative value. When the DC motor 10 isdriven, the reel shaft 3 rotates such that current flowing to the DCmotor 10 varies. Therefore, the time is accumulated so long as thecurrent varies, and the accumulated time is used to determine the amountof retraction or protraction of the seatbelt.

Although in the above described embodiment the control executed by theMPU 14 is carried out irrespective of the traveling speed of theautomotive vehicle, preferably the seatbelt slackening control may becarried out when the traveling speed is higher than a predeterminedvalue and the seatbelt storing control when the traveling speed is lowerthan a predetermined value.

Seventh Embodiment

An automotive passenger restraint and protection apparatus according toa seventh embodiment of the invention includes an electric retractor700, which is distinguished from the electric retractor 100 of FIG. 1 inthat a detecting circuit 45 is provided in place of the temperaturesensor 19.

The detecting circuit 45 is connected to the DC motor driver 11, the MPU14, and the buckle connection detector 16, and delivers a mode controlsignal for selecting a reduced power consumption mode or a normal powerconsumption mode, based upon a voltage signal generated by protractionof the seatbelt by the occupant or a voltage signal from the buckleconnection detector 16. Except for the above, the construction of theelectric retractor 700 is identical with that of the electric retractor100, illustration and description of which are therefore omitted.

FIG. 31 is a circuit diagram showing the arrangements of the DC motordriver 11, the detecting circuit 45 and the buckle connection detector16 according to the seventh embodiment. In FIG. 31, reference numeral P7designates an input terminal for receiving a control signal delivered tothe detecting circuit 45 from the MPU 14, and reference numeral P8designates an output terminal for outputting the mode control signal forselecting the reduced power consumption mode or the normal powerconsumption mode, to the MPU 14. The reduced power consumption mode is amode for stopping all the functions of the MPU 14 except for a functionof receiving the mode control signal, and the normal power consumptionmode is a mode for allowing all the functions of the MPU 14 to operate.

The detecting circuit 45 includes a NAND circuit which has one inputterminal thereof serving as the input terminal P7, and the other inputterminal connected to an output terminal of an OR circuit 46. An outputterminal of the NAND circuit serves as the output terminal P8. The ORcircuit 46 has one input terminal thereof connected between thecapacitor C3 of the IF IF4 and the output terminal P6 at a junction Q1,and the other input terminal connected to an output terminal of a NOTcircuit 47, which in turn has an input terminal thereof connected to thebattery Vb through a resistance 49, as well as to ground via a switch 48which closes when the tongue of the seatbelt is attached to the buckle.The input terminal of the NOT circuit 47 is connected to a junctionbetween voltage dividing resistances 49 and 50 serially connectedbetween the battery Vb and ground. The switch 48 and the resistances 49,50 are components of the buckle connection detector 16.

The OR circuit 46 receives a high-level (H) signal from the junction Q1when the seatbelt is protracted by the occupant. The switch 48 closeswhen the tongue of the seatbelt is connected to the buckle by theoccupant, and then the NOT circuit 47 delivers a high-level (H) signalto the OR circuit 46. When no protraction of the seatbelt is made by theoccupant and when the seatbelt tongue is not connected to the buckle, alow-level (L) signal is input to the OR circuit 46.

FIGS. 32A to 32D show changes in an output signal (mode control signal)delivered from the output terminal P8 to the MPU 14 and modes of the MPU14 corresponding to the changes.

First, as shown in FIG. 32A, when the output signal from the outputterminal P8 turns from a high level H to a low level L, the MPU 14enters the normal power consumption mode. As shown in FIG. 32B, when themode control signal from the output terminal P8 turns from the low levelL to the high level H, the MPU 14 enters the reduced power consumptionmode. When the mode control signal remains at the low-level L (FIG. 32C)or when the mode control signal remains at the high level L (FIG. 32D),the MPU 14 remains in the same mode without a change in the mode.

FIG. 33 is a flowchart showing reduced power consumption controlexecuted by the MPU 14. This control forms part of main control executedby the MPU 14 and is executed when the storage of the seatbelt has beencompleted.

In an initial state, the MPU 14 sets itself into the normal powerconsumption mode at a step S3401. Then, it is determined at a step S3402whether attaching of the seatbelt tongue to the buckle has been detectedby the buckle connection detector 16. If attaching of the seatbelttongue to the buckle has not been detected, the present processing isimmediately terminated, whereas if attaching of the seatbelt tongue hasbeen detected, it is determined at a step S3403 whether a predeterminedtime period t (e.g. 3 sec) has elapsed, from the value of the timer 15.If the predetermined time period t has not yet elapsed, the samedetermination is repeated, whereas if the predetermined time period thas elapsed, the MPU 14 delivers a high-level (H) control signal to thedetecting circuit 45 through the input terminal P7 at a step S3404, andthe power consumption mode is set to the reduced power consumption modeat a step S3405.

Then, it is determined at a step S3406 whether the mode control signalfrom the detecting circuit 45 has turned to the low level (L). On thisoccasion, the mode control signal goes low if the high-level (H) signalindicative of protraction of the seatbelt by the occupant or thehigh-level (H) signal indicative of attaching of the seatbelt tongue tothe buckle is delivered through the OR circuit 46 to the detectingcircuit 45. If the mode control signal has not turned to the low level(L), the same determination is repeated, whereas if the mode controlsignal has turned to the low level (L), the power consumption mode isset to the normal power consumption mode at a step S3407. Then, alow-level (L) control signal is delivered to the detecting circuit 45through the input terminal P7 at a step S3408, followed by terminatingthe present processing.

As described above, according to the present embodiment, upon the lapseof the predetermined time period t after disconnection of the seatbeltfrom the occupant is detected while the MPU 14 is in the normal powerconsumption mode, the power consumption mode is set to the reduced powerconsumption mode whereby all the functions of the MPU 14 are stoppedexcept for the function of receiving the mode control signal.Thereafter, when protraction of the seatbelt by the occupant orattaching of the seatbelt tongue to the buckle is detected, the powerconsumption mode is set to the normal power consumption mode whereby allthe functions of the MPU 14 can be resumed. Thus, it is possible tochange the operative state of the MPU 14 according to the expectedability thereof to thereby reduce the power consumption.

Eighth Embodiment

FIG. 34 shows the arrangement of an electric retractor 800 provided inan automotive passenger restraint and protection apparatus according toan eighth embodiment of the invention.

In FIG. 34, the DC motor driver 11 is connected to a power source 63which supplies the DC motor driver 11 with supply power required fordriving the DC motor 10. The electric retractor 800 includes adriving/traveling state detector 55 for detecting states of driving andtraveling of the automotive vehicle by the occupant, which is comprisedof an MPU 54 which is connected to the MPU 14, a distance sensor 52, asteering angle sensor 53, and a DC-DC converter 56.

The MPU 14 is connected to the power source 63 through a DC-DC converter64 which converts supply voltage from the power source 63 to a levelsuitable for operation of the MPU 14, e.g. 5 volts. A transistor 58 hasa base thereof connected through a resistance 57 to the MPU 14. Thetransistor 58 has an emitter thereof grounded and a collector thereofconnected through a resistance 59 to a coil 61 of a relay circuit 60.The coil 61 is connected to the power source 63, which is connectedthrough contacts 62 of the relay circuit 60 to the DC-DC converter 56which converts supply voltage from the power source 63 to a levelsuitable for operation of the MPU 14 as well as the distance sensor 52and the steering angle sensor 53, e.g. 5 volts. The DC-DC converter 56is connected to the MPU 54 as well as the distance sensor 52 andsteering angle sensor 53 which are connected to the MPU 54.

The distance sensor 52 detects the distance between the present vehicle(occupant's vehicle) and an object lying ahead of the vehicle, and thesteering angle sensor 53 senses the steering angle of a steering arm ofthe vehicle.

The MPU 14 determines whether protraction of the seatbelt has been made,from the sign of terminal voltage across the DC motor 10, and alsodetermines whether retraction of the seatbelt has been completed, fromthe current i flowing to the DC motor 10.

Next, the flow of control signals at various components of theautomotive passenger restraint and protection apparatus according to thepresent embodiment will be described.

The distance sensor 52 delivers an output signal indicative of resultsof detection of the distance between the present vehicle and an objectlying ahead of the vehicle to the MPU 54. The MPU 54 calculates a safetydistance ds (m) between the present vehicle and an object lying ahead bythe use of the following formula (1), and when the calculated safetydistance ds is larger than a value indicated by the output signal fromthe distance sensor 52, the MPU 54 delivers an output signal forcollision danger warning to the MPU 14. Further, the MPU 54 calculates acollision unavoidable distance dd (m) by the use of the followingformula (2), and when the calculated collision unavoidable distance ddis larger than a value indicated by the output signal from the distancesensor 52, the MPU 54 delivers an output signal indicative of acollision being unavoidable, to the MPU 14.ds=Vr×(td+β)  (1)dd=Vr×td  (2)where Vr represents relative speed (m/sec), td response delay of thedriver (e.g. 0.5 to 2 sec), and β a value determined by the brakingcharacteristic of the vehicle (e.g. 0.5 to 2 sec).

The steering angle sensor 53 delivers an output signal indicative of thesensed steering angle to the MPU 54, and when the maximum value ofchange amount in the detected steering angle within a prescribed timeperiod (e.g. 2 sec) is less than a predetermined value (e.g. 8 degrees),the MPU 15 judges that the driver might be dozing and delivers an outputsignal for doze warning to the MPU 14.

The buckle connection detector 16 detects whether the tongue of theseatbelt has been connected to the buckle, and delivers an output signalindicative of results of the detection to the MPU 14. The DC motordriver 11 controls the rotation of the DC motor 10, based upon a controlsignal from the MPU 14.

The MPU 14 operates in response to the signal from the buckle connectiondetector 16, indicating that the seatbelt tongue has been connected tothe buckle, to deliver a high-level signal to the transistor 58 throughthe resistance 57, whereby the transistor 58 is turned on to permitcurrent to flow from the power source 63 to the coil 61 to close thecontacts 62, and permit supply voltage to be supplied to the MPU 54 aswell as to the distance sensor 52 and the steering angle sensor 53. Onthe other hand, when the signal from the buckle connection detector 16,indicating that the seatbelt tongue has been connected to the buckle hasceased to be delivered to the MPU 14, the MPU 14 delivers a low-levelsignal to the transistor 58, whereby the transistor 58 is turned off tostop supply of current from the power source 63 to the coil 61 to openthe contacts 62 and stop supply of the supply voltage to the MPU 54 aswell as to the distance sensor 52 and the steering angle sensor 53.

As described above, according to the present embodiment, it iscontrolled such that when the seatbelt is in the attached state, supplyvoltage from the power source is supplied to the MPU 54 nor to thedistance sensor 52 and the steering angle sensor 53, while when theseatbelt is in the disconnected state, supply voltage from the powersource is not supplied to the MPU 54 nor to the distance sensor 52 andthe steering angle sensor 53. Thus, only when it is necessary to operatethese components, the supply voltage can be supplied, thereby reducingthe power consumption.

Although in the present embodiment the control of supply voltage to theMPU 54, etc. is made depending upon whether the seatbelt is in theattached state or in the disconnected state, this is not limitative. Forexample, alternatively the control of supply voltage to the MPU 54 andits peripheral components may be carried out depending upon a shiftposition of a transmission of the automotive vehicle, providingsubstantially the same results. More specifically, a shift positionsensor may be connected to the MPU 14, and if the detected shiftposition is the parking position, the supply of power to the MPU 54 andits peripheral components is inhibited, while if the detected shiftposition is other than the parking position, the supply of the MPU 14,etc. is permitted. Further, the control of supply voltage to the MPU 54and its peripheral components may be carried out depending upon whethera parking brake of the automotive vehicle is pulled up or in operativeposition, providing substantially the same results. More specifically, aparking brake position sensor may be connected to the MPU 14, and if thedetected parking brake position is the pulled-up or operative position,the supply of power to the MPU 54 and its peripheral components isinhibited, while if the detected parking brake position is other thanthe pulled-up or operative position, the supply of the MPU 14, etc. ispermitted.

Ninth Embodiment

An electric retractor provided in an automotive passenger restraint andprotection apparatus according to a ninth embodiment of the invention isidentical in construction with the electric retractor 100, illustrationand description of which are therefore omitted.

FIG. 35 is a flowchart showing seatbelt storing control according to theninth embodiment, executed by the MPU 14 in retracting the seatbelt.

First, it is determined at a step S3601 whether disconnection of theseatbelt tongue from the buckle has been detected by the buckleconnection detector 16. If disconnection of the seatbelt tongue has notbeen detected, the present processing is immediately terminated, whereasif disconnection of the seatbelt tongue has been detected, a controlsignal is delivered to the DC motor driver 11 to rotate the reel shaft 3in the seatbelt retracting direction at a step S3602, whereby theseatbelt is retracted. On this occasion, the timer 15 measures timeelapsed after the start of delivery of the control signal to the DCmotor driver 11.

Then, it is determined at a step S3603 whether a predetermined timeperiod (e.g. 3 sec) has elapsed after the start of delivery of thecontrol signal to the DC motor driver 11. Upon the lapse of thepredetermined time period, a control signal is delivered to the DC motordriver 11 to stop the rotation of the reel shaft 3 at a step S3504,whereby the rotation of the reel shaft 3 is stopped. On this occasion,it is assumed that locking of the seatbelt by the seatbelt lockingmechanism 2 does not take place. On this occasion, the timer 15 measurestime elapsed after the delivery of the control signal to the DC motordriver 11 to stop the rotation of the reel shaft 3.

Then, it is determined at a step S3605 whether protraction of theseatbelt has been made. If protraction of the seatbelt has been made,seatbelt protraction control is executed, as described hereinafter. Ifprotraction of the seatbelt has not been made, it is determined at astep S3606 whether a predetermined time period (e.g. 10 sec) has elapsedafter the delivery of the control signal to the DC motor driver 11 tostop the rotation of the reel shaft 3. If the predetermined time periodhas not yet elapsed, the processing returns to the step S3605, whereasif it has elapsed, a control signal is delivered to the DC motor driver11 to rotate the reel shaft 3 in the seatbelt retracting direction at astep S3607, whereby the seatbelt is retracted.

Then, it is determined at a step S3608 whether the retraction of theseatbelt has been completed. If the completion of the retraction hasbeen completed, a control signal is delivered to the DC motor driver 11to stop the rotation of the reel shaft 3 at a step S3609, and then theseatbelt protraction control is executed, as described hereinafter, at astep S3610, followed by terminating the present processing.

FIG. 36 is a flowchart showing seatbelt protraction control according tothe ninth embodiment, executed by the MPU 14 in protracting theseatbelt.

First, it is determined at a step S3701 whether attaching of theseatbelt tongue to the buckle has been detected by the seatbeltconnection detector 16. If attaching of the seatbelt tongue to thebuckle has been detected, it is regarded that the protraction of theseatbelt has been completed, and a control signal is delivered to the DCmotor driver 11 to stop the rotation of the reel shaft 3 at a stepS3708, followed by terminating the present processing. On the otherhand, if attaching of the seatbelt tongue to the buckle has not beendetected, a control signal is delivered to the DC motor driver 11 tostop the rotation of the reel shaft 3 so as to execute assisting of theprotraction of the seatbelt at a step S3702.

Then, the terminal voltage across the DC motor 10 and the sign thereofare measured by the circuit C2 of the DC motor driver 11 at a stepS3703. It is determined whether the measured terminal voltage exceeds apredetermined value (e.g. 0.3 volts) and at the same time the sign ofthe terminal voltage corresponds to the direction of protracting theseatbelt at a step S3704. The answer to this question becomesaffirmative (YES) if the occupant lightly protracts the seatbelt.

If it is determined at the step S3704 that the terminal voltage does notexceed the predetermined value (0.3 volts) or the sign does notcorrespond to the direction of protracting the seatbelt, the processingreturns to the step S3703, whereas if the terminal voltage exceeds thepredetermined value (0.3 volts) and at the same time the sign of theterminal voltage corresponds to the direction of protracting theseatbelt, the MPU 14 delivers a control signal commanding to rotate thereel shaft 3 in the seatbelt protracting direction, to the DC motordriver 11 at a step S3705, whereby the seatbelt can be easilyprotracted.

According to the control of the steps S3701 to S3705 described above,when the measured terminal voltage exceeds the predetermined value (0.3volts) and at the same time the sign of the terminal voltage correspondsto the direction of protracting the seatbelt, the seatbelt can bebrought into a state where it can be easily protracted. As a result, alarge force as required in the conventional apparatus is not needed, andtherefore even a weak occupant who has degraded physical ability such asan advanced-age occupant can easily mount the seatbelt onto his body.

Then, it is determined at a step S3706 whether attaching of the tongueof the seatbelt has been detected by the buckle connection detector 16.If attaching of the seatbelt has been detected, the processing proceedsto the step S3708. On the other hand, if attaching of the seatbelt hasnot been detected, it is determined at a step S3707 whether apredetermined time period (e.g. 7 sec) has elapsed after the controlsignal commanding to rotate the reel shaft 3 was delivered to the DCmotor driver 11.

If the predetermined time period has not elapsed, the processing returnsto the step S3705, whereas if it has elapsed, which means that theseatbelt has been protracted but the tongue of the seatbelt has not beenconnected to the buckle such that the seatbelt is in a slackened state,a control signal commanding to stop the rotation of the reel shaft 3 isdelivered to the DC motor driver 11 at a step S3708, followed byterminating the present processing.

As described above, according to the present embodiment, whendisconnection of the seatbelt tongue from the buckle has been detected,retraction of the seatbelt is started. Then, before completion of theretraction, the retraction of the seatbelt is stopped by stopping therotation of the reel shaft 3 for a predetermined time period. If theseatbelt is protracted during the predetermined time period, theseatbelt protraction control is executed, whereas if the seatbelt is notprotracted over the predetermined time period, retraction of theseatbelt is carried out. Therefore, in the case where if the seatbelttongue is once disconnected from the buckle and soon then the seatbelttongue is connected to the buckle, it is not necessary to protract orpull the seatbelt against the retracting force of the electricretractor, as is distinct from the conventional automotive passengerrestraint and protection apparatus, to thereby facilitate mounting ofthe seatbelt onto the occupant.

Although in the present embodiment the retraction of the seatbelt isstopped only one time over the predetermined time period beforecompletion of the retraction (steps S3604 to S3606), the stopping of theretraction may be made a plurality of times.

Tenth Embodiment

FIG. 37 shows the arrangement of an automotive passenger restraint andprotection apparatus according to a tenth embodiment of the invention.The automotive passenger restraint and protection apparatus according tothe present embodiment is comprised of a collision danger predictor 66,a speed detector 67, a controller 68, a driver 69, and a retractor mainbody 70.

The collision danger predictor 66 is adapted to generate a collisionunavoidableness signal indicating that a degree of danger of collisionof the automotive vehicle with an obstacle lying ahead has reached sucha degree that the collision cannot be avoided only through operation ofthe driver, and a collision danger signal indicating that a danger ofcollision is impending but the collision can be avoided throughoperation of the driver. The speed detector 67 generates a signalindicative of the traveling speed of the automotive vehicle.

The controller 68 controls the driver 69, based upon the signals fromthe collision danger predictor 66 and the speed sensor 67. The driver 69drives the retractor main body 70 which carries out retraction andprotraction of the seatbelt.

FIG. 38 shows details of the arrangement of the automotive passengerrestraint and protection apparatus according to the tenth embodiment.The collision danger predictor 66 is comprised of a relative distancesensor 71, a doze sensor 72, an interface (I/F) 73, and a microcomputerunit (MCU) 74. The relative distance sensor 71 is adapted to generate avoltage signal corresponding to the distance between an obstacle and thepresent automotive vehicle. The doze sensor 72 is adapted to detect achange in the steering angle sensed by a steering angle sensor providedin a steering of the automotive vehicle and generate a signal indicativeof a doze of the driver if the change in the steering angle exceeds apredetermined value, for example.

The speed detector 67 is formed of a speed sensor 75 and generates anddelivers a signal indicative of the sensed traveling speed V of thevehicle to the MPU 74 via the interface 73.

The controller 68 is mainly comprised of the MCU 74, to which areconnected via the interface 73 the relative distance sensor 71, the dozesensor 72 and the speed sensor 75. The MCU 74 stores in an internalmemory thereof the traveling speed V of the vehicle sensed by the speedsensor 75 and produces the collision danger signal and the collisionunavoidableness signal based upon output signals from the relativedistance sensor 71 and the doze sensor 72 and delivers these signals toswitches SW1, SW2, and SW3.

The driver 69 is comprised of a motor 78, the switches SW1, SW2, andSW3, a DC power source 76, and an oscillator 77. When the collisiondanger signal is received from the MCU 74, the driver 69 operates inresponse to the collision danger signal to close the switch SW1 and atsame time cause movable contacts of the switches SW2 and SW3 to beconnected to respective fixed contacts A, whereby an output signal fromthe oscillator 77 is delivered to the motor 78. The oscillator 77 has anoscillation frequency of 20 Hz in the present embodiment.

When the collision unavoidableness signal is received from the MCU 74,the driver 69 operates in response to the collision unavoidablenesssignal to close the switch SW1 and at the same time causes the movablecontacts of the switches SW2 and SW3 to be connected to respective fixedcontacts B, whereby output voltage from the DC power source 76 isapplied to the motor 78.

FIGS. 39A and 39B schematically show the construction of a seatbeltdevice with the electric retractor according to the present embodiment.In the seatbelt device, a seatbelt 79 with one end thereof fixed to astationary shaft 80 extends through a buckle 81, a shoulder portion 82and is wound on the retractor main body 70. When the motor 78, which isdirectly coupled to the retractor main body 70, is driven, retraction orprotraction of the seatbelt 79 is carried out while the tension of theseatbelt 79 is increased or decreased.

FIG. 40 is a flowchart showing a manner of operation of the automotivepassenger restraint and protection apparatus according to the presentembodiment.

This processing is executed at predetermined time intervals during atime period of seatbelt attaching as electric retractor control. First,it is determined at a step S4101 whether a collision of the vehicle withan obstacle lying ahead is unavoidable. If the collision is notunavoidable, it is determined at a step S4102 whether there is a dangeror possibility of a collision of the vehicle with an obstacle lyingahead. More specifically, these determinations are carried out in thefollowing manner:

That is, a relative distance Δd between the vehicle and the obstacle isdetected by the relative distance sensor 71. Based upon the detectedrelative distance Δd, a relative speed ΔV between the obstacle and thevehicle (=Δdi−Δdi−1) is calculated. Based upon the calculated relativespeed ΔV, a time period t before the expected collision (=Δd/ΔV) isestimated.

It is determined whether the time period t before the expected collisionexceeds a predetermined time period t1, that is, whether there is apossibility of collision. If the time period t before the expectedcollision is shorter than the predetermined time period t1, it isdetermined whether the time period t before the expected collision isequal to or longer than a predetermined time period t2 which is shorterthan the predetermined time period t1. If the time period t is shorterthan the predetermined time period t2, it is judged that a collision ofthe vehicle with the obstacle lying ahead cannot be avoided only throughoperation of the driver, and then the MPU 74 generates the collisionunavoidableness signal. On the other hand, if the time period t is equalto or longer than the predetermined time period t2, the MPU 74 generatesthe collision danger signal.

Further, on the other hand, if the time period t before the expectedcollision is equal to or longer than the predetermined time period t1,it is determined whether a signal has been generated from the dozesensor 72, which indicates that the driver is dozing, and if the signalhas been generated, the MPU 74 generates the collision danger signal. Onthe other hand, if th signal has not been generated, it is regarded thatthere is no possibility of collision, and then the MCU 74 does notgenerate the collision danger signal.

If it is determined at the step S4101 that a collision of the vehiclewith an obstacle lying ahead is unavoidable, the MCU 74 delivers thecollision unavoidableness signal to the switches SW1, SW2, and SW3 toclose the switch SW1 and cause the movable contacts of the switches SW2and SW3 to be connected to the respective fixed contacts B, wherebyoutput voltage from the DC power source 76 is applied to the motor 78 todrive the same to start retraction of the seatbelt 79 at a step S4103.Then, the lapse of a predetermined time period is waited at a stepS4104. Upon the lapse of the predetermined time period, the retractionis stopped at a step S4105, followed by terminating the processing. Thispredetermined value is set to a time period within which the tension ofthe seatbelt 79 can be increased by the driving of the motor 78 toproperly fasten or restrain the occupant.

On the other hand, if it is determined at the step S4102 that there is adanger of a collision of the vehicle with an obstacle lying ahead, theMPU 74 delivers the collision danger signal to the switches SW1, SW2,and SW3 to close the switch SW1 and cause the movable contacts of theswitches SW2 and SW3 to be connected to the respective fixed contacts A,whereby an output signal (frequency: 20 Hz) from the oscillator 77 issupplied to the motor 78 to drive the same to cause alternate retractionand protraction of the seatbelt 79 onto or from the retractor main body70 to periodically increase and decrease or generate vibration byapplying pressure to and release the same from the occupant at a stepS4106. Then, the traveling speed V1 of the present vehicle sensed by thespeed sensor 75 is stored in the internal memory of the MCU 74 at a stepS4107, followed by terminating the present processing.

On the other hand, if it is determined at the step S4102 that there isno danger of collision and hence the collision danger signal is notgenerated, it is determined at a step S4108 whether a difference ΔVbetween the traveling speed V1 of the present vehicle stored at the stepS4107 and a current traveling speed V2 of the present vehicle exceeds apredetermined value. The predetermined value is set to such a value thatthe vehicle has been sufficiently decelerated after the collision dangersignal ceased to be generated and the vehicle cannot be expected toenter a dangerous state.

If it is determined that the speed difference ΔV exceeds thepredetermined value, it is judged that a dangerous state has been fullyobviated, and then the MCU 74 delivers a signal to the switch SW1 toopen the same to thereby deenergize the motor 78 to stop the vibrationof the seatbelt at a step S4109. On the other hand, if the speeddifference ΔV does not exceed the predetermined value, it is judged thata dangerous state has not yet been fully obviated, and then the MCU 74keeps the switch SW1 closed and the movable contacts of the switches SW2and SW3 connected to the respective fixed contacts A, followed byterminating the processing.

As described above, according to the present embodiment, when it isdetermined that there is no danger of a collision of the vehicle with anobstacle to stop generation of the collision danger signal, it isdetermined whether the speed difference ΔV between the stored travelingspeed V1 of the vehicle and the current traveling speed V2 of thevehicle exceeds a predetermined value, and if the former does not exceedthe latter, it is judged that a dangerous state has not been fullyobviated, and then the processing is terminated without stoppingvibration of the seatbelt. As a result, so long as it can be expectedthat the vehicle enters a dangerous state even after the collisiondanger signal ceases to be generated, vibration is continued byalternately applying pressure and release the same to and from theoccupant to thereby fully alert the occupant to the danger. Thus, theautomotive passenger restraint and protection apparatus can beeffectively utilized as a warning device.

Although in the present embodiment the switches SW1 to SW3 are switchedby signals from the MCU 74 to selectively deliver supply voltage fromthe DC power source 76 or the output from the oscillator 77 to the motor78, this is not limitative, but, for example, an interface circuit fordetecting terminal voltage across the motor or supply current to themotor and a motor driving circuit may be provided such that the MCU 14detects the terminal voltage or the supply current and controls themotor driving circuit based upon the detected terminal voltage or supplycurrent to thereby drive the motor 78 for retraction and protraction ofthe seatbelt.

Eleventh Embodiment

An automotive passenger restraint and protection apparatus according toan eleventh embodiment of the invention includes an electric retractor1100, which is distinguished from the electric retractor 100 of FIG. 1in that an A/D converter 83 is included in the MPU 14, for samplingvoltage signals every predetermined time period. Except for this, theconstruction of the electric retractor 1100 is identical with that ofthe electric retractor 100, illustration and description of which aretherefore omitted.

The MPU 14 receives voltage signals from the IFs IF3 and IF4 in FIG. 2and measures terminal voltage across the DC motor 10, based upon thereceived voltage signals. FIG. 41A shows an example of the waveform ofterminal voltage across the DC motor 10 containing pulsating componentsassumed when the seatbelt is slowly protracted by the occupant, and FIG.41B shows an example of the waveform of terminal voltage across the DCmotor 10 containing pulsating components assumed when the seatbelt isquickly protracted by the occupant.

FIG. 42 is a flowchart showing a control program according to theeleventh embodiment, executed by the MPU 14.

First, it is determined at a step S4301 whether attaching of theseatbelt tongue to the buckle has been detected by the buckle connectiondetector 16. If attaching of the seatbelt tongue to the buckle has beendetected, the present processing is immediately terminated, whereas ifattaching of the seatbelt tongue to the buckle has not been detected, itis determined at a step S4302 whether the seatbelt is being protracted,from the terminal voltage across the DC motor 10. If the seatbelt is notbeing protracted, the same determination is repeated, whereas if theseatbelt is being protracted, the terminal voltage across the DC motor10 is measured at a step S4303. More specifically, an amount ofprotraction of the seatbelt over a predetermined time period (e.g. 0.5sec) is calculated from the measured terminal voltage.

An example of the manner of calculating the amount of protraction of theseatbelt, i.e. a length of the seatbelt protracted will be describedhereinbelow.

FIG. 43 is a block diagram showing contents of arithmetic processingexecuted by the MPU 14 according to the present embodiment provided inthe electric retractor 1100.

The MPU 14 is comprised of a digital filtering block (high-pass filter)84 for extracting only pulsating components from voltage signals fromthe IFs IF3 and IF4, a counting block 85 for counting a number of timesthe extracted pulsating components rise a predetermined voltage v0 (e.g.1 volt) from a level below the predetermined voltage, aprotraction/retraction amount calculating block 86 for calculating anamount of protraction or retraction of the seatbelt, based upon a countvalue obtained by the counting block 85, a digital filtering block(low-pass filter) 87 for removing only pulsating components from thevoltage signals from the IFs IF3 and IF4, and a motor rotationaldirection detecting block 88 for detecting whether the rotationaldirection of the DC motor 10 is in the seatbelt protracting direction orin the seatbelt retracting direction, based upon the sign of the voltagesignals with pulsating components removed therefrom.

Next, the operation of these blocks of the electric retractor 1100 forcalculating the protraction amount or the retraction amount of theseatbelt will be described.

When the seatbelt has been protracted by the occupant, the reel shaft 3is rotated, and the rotation is transmitted through the reel shaftpulley 5, the DC motor pulley 6, and the power transmission belt 7 tothe rotary shaft of the DC motor 10 to rotate the same, whereby anelectromotive force is generated. The A/D converter 83 samples theresulting voltage signals from the IFs IF3 and IF4 every predeterminedtime period.

In the digital filtering block 84, the voltage signal from the IF IF4 issubtracted from the voltage signal from the IF IF3, and the resultingdifference voltage is subjected to high-pass filtering to extract onlypulsating components therefrom. The counting block 85 counts the numberof times the extracted pulsating components rise above the predeterminedvalue V0 from a level below the same, and a signal indicative of thecount value is delivered to the protraction/retraction amountcalculating block 86.

On the other hand, in the digital filtering block 87, the voltage signalfrom the IF IF4 is subtracted from the voltage signal from the IF IF3,and the resulting difference voltage is subjected to low-pass filteringto remove only pulsating components therefrom. The resulting voltagesignal free of pulsating components is delivered to the motor rotationaldirection detecting block 88, which in turn detects whether therotational direction of the DC motor 10 is in the seatbelt protractingdirection or in the seatbelt retracting direction, based upon the signof the voltage signals free of pulsating components, and delivers asignal indicative of results of the detection (the seatbelt protractingdirection in the present case) to the protraction/retraction amountcalculating block 86.

In the protraction/retraction amount calculating block 86, the countvalue from the counting block 85 is multiplied by a predetermined value(e.g. 10 cm/1 count), and the amount of protraction of the seatbelt iscalculated based upon the resulting product and the signal indicative ofthe detected rotational direction of the DC motor 10 from the motorrotational direction detecting block 88.

Referring back to FIG. 42, after the calculation of the length of theseatbelt over the predetermined time period (0.5 sec) at the step S4304,the speed v of protracting the seatbelt is calculated at a step S4305,and based upon the calculated protracting speed v, a waiting time t1after stoppage of protraction of the seatbelt is set at a step S4306.The waiting time t1 is set in the following manner, for example:

TABLE 1 PROTRACTING SPEED v (m/s) WAITING TIME t1 (s) v > 0.5 t1 = 1.50.5 ≧ v ≧ 0.3 t1 = 3   0.3 > v t1 = 5  

The above setting of the waiting time t1 takes into consideration thefact that in the case of an occupant having a high physical ability, theseatbelt protracting speed is high and the time period after stoppage ofprotraction of the seatbelt by the occupant and before completion ofmounting of the seatbelt onto his body is relatively short, whereas inthe case of an occupant having a low physical ability, the seatbeltprotracting speed is low and the time period after the occupantprotracts and before completion of mounting of the seatbelt onto hisbody is relatively long.

Next, it is determined at a step S4307 whether the protraction of theseatbelt has been terminated, from the current i flowing to the DC motor10. If the protraction has not been terminated, the processing returnsto the step S4303, whereas if the protraction has been terminated, it isdetermined at a step S4308 whether the waiting time t1 has elapsed afterthe termination of protraction of the seatbelt. If the waiting time t1has elapsed, the seat storing control of FIG. 18 is executed at a stepS4309, followed by terminating the present processing. If the waitingtime t1 has not elapsed, it is determined at a step S4310 whetherattaching of the seatbelt tongue to the buckle has been again detectedby the buckle connection detector 16. If attaching of the seatbelttongue has not been detected, the processing returns to the step S4308,whereas if attaching of the seatbelt tongue has been detected, thepresent processing is terminated.

As described above, according to the present embodiment, the waitingtime t1 after the stoppage of protraction of the seatbelt is setaccording to the seatbelt protracting speed. As a result, even when anoccupant of a high physical ability gets off the vehicle and closes thedoor in a short time after protracting the seatbelt, it can be preventedthat the seatbelt is caught in the door. On the other hand, when anoccupant of a low physical ability mounts the seatbelt onto his body, itcan be prevented that the seatbelt starts to be retracted before hefinishes mounting the seatbelt onto his body to impede his mountingmotion, whereby a comfortable seatbelt attaching environment isprovided.

Twelfth Embodiment

An automotive passenger restraint and protection apparatus according toa twelfth embodiment of the invention includes an electric retractor1200, which is distinguished from the electric retractor 100 of FIG. 1in that a danger degree detector 89 for detecting a degree of danger ofcollision of the automotive vehicle is connected to the MPU 14, in placeof the temperature sensor 19 in FIG. 1. Except for this, theconstruction of the electric retractor 1200 is identical with that ofthe electric retractor 100, description of which is therefore omitted.

FIG. 44 shows the arrangement of the electric retractor 1200 accordingto the present embodiment.

As shown in FIG. 44, the danger degree detector 89 is connected to theMPU 14.

The danger degree detector 89 is comprised of a vehicle speed sensor 90for sensing the traveling speed of the automotive vehicle, a brakingdetector 91 for detecting stepping-on of a brake pedal of the automotivevehicle, a steering angle detector 92 for detecting the steering angleof a steering arm of the vehicle, an ambient illuminance detector 93 fordetecting ambient illuminance of the vehicle, and a raindrop detector 94for sensing raindrops.

FIG. 45 is a schematic view showing the interior of the vehiclecompartment, which is applied to the present embodiment.

Fixed to an inner wall of the vehicle compartment is a support shaft ofthe brake pedal which is normally biased in a non-stepped-on position bya spring. Mounted within the support shaft of the brake pedal is anangle sensor, not shown, which rotates in unison with movement of thebrake pedal and is connected to the braking detector 91 in FIG. 44.

The braking detector 91 calculates the stepping-on force from an anglesensed by the angle sensor to thereby detect stepping-on of the brake,and calculates the stepping-on speed, from a time change in the sensedangle.

Alternatively, the braking detector 91 may detect whether decelerationof the automotive vehicle sensed by a G sensor or a like sensor issmaller than a predetermined value, or whether a time change in thevehicle speed sensed by the vehicle sensor 90 exceeds a predetermineddegree of deceleration.

The steering angle detector 92 is connected to a potentiometer rotatablein unison with rotation of a column at the center of the steering armand detects the steering angle, based upon a signal from thepotentiometer. Further, the steering angle detector 92 also detects arate of change in the steering angle, from a time change in the steeringangle.

The ambient illuminance detector 93 is connected to a photo sensor suchas a photo diode. The photo sensor is arranged between an internalmirror of the automotive vehicle and a windshield of the same, forreceiving light from the outside through the windshield. An outputsignal indicative of the sensed intensity of light from the photo sensoris delivered to the ambient illuminance detector 93, which in turndetects the ambient illuminance from the output signal.

The raindrop detector 94 is connected to two electrodes on an insulatingboard arranged on a bonnet of the vehicle. The resistance between thetwo electrodes varies with the amount of raindrops, and a signalindicative of the amount of raindrops is delivered to the raindropdetector 94, which in turn detects the presence of raindrops from thesignal.

FIG. 46 is a flowchart showing a control program according to thepresent embodiment, executed by the MPU 14.

First, it is determined at a step S4601 whether attaching of theseatbelt tongue to the buckle has been detected by the buckle connectiondetector 16. If attaching of the seatbelt tongue has not been detected,the present processing is immediately terminated, whereas if attachingof the seatbelt tongue has been detected, it is determined at a stepS4602 whether a significant degree of danger has been detected by thedanger degree detector 89. It is determined that the significant degreeof danger has been detected, if the vehicle speed detected by thevehicle speed detector 90 exceeds a predetermined value (e.g. 60 km/h)and at the same time at least one of the following conditions isdetected:

(1) Braking has been detected by the braking detector 91;

(2) The rate of change in the steering angle detected by the steeringangle detector 92 exceeds a predetermined value;

(3) The ambient illuminance detected by the ambient illuminance detector94 exceeds a predetermined value; and

(4) Raindrops have been detected by the raindrop detector 94.

If it is determined at the step S4602 that the significant degree ofdanger has not been detected, first seatbelt slackening control,described hereinafter, is executed at a step S4603, whereas if thesignificant degree of danger has been detected, second seatbeltslackening control, described hereinafter, is executed at a step S4604,followed by terminating the present processing.

The present control program is executed every predetermined time periodt1 (e.g. 0.1 sec). However, when the determination as to the significantdegree of danger at the step S4602 continuously provides the sameresult, the first or second seatbelt slackening control is executed onlywhen the result of the first determination is obtained, but the samecontrol is not executed when the results of the second determination etseq. are obtained.

FIG. 47 is a flowchart showing the first seatbelt slackening controlaccording to the present embodiment.

First, a PWM signal is delivered from the MPU 14 to the DC motor driver11 to rotatively drive the DC motor 10 in the seatbelt retractingdirection at a step S4701, and then it is determined at a step S4702whether the retraction of the seatbelt has reached its limit, fromcurrent flowing to the DC motor 10. When the retraction of the seatbelthas reached its limit, an improper looseness of the seatbelt has beencompletely removed.

If it is determined at the step S4702 that the retraction of theseatbelt has not reached its limit, the processing returns to the stepS4701, whereas if the retraction has reached the limit, a PWM signal isdelivered from the MPU 14 to the DC motor driver 11 to rotatively drivethe DC motor 10 in the seatbelt protracting direction at a step S4703,and then it is determined at a step S4704 whether a predetermined timeperiod t2 (e.g. 1 sec) has elapsed after the start of the driving of theDC motor 10 in the seatbelt protracting direction. When thepredetermined time period t2 has elapsed, a proper amount of loosenesshas been given to the seatbelt and hence to the occupant.

If it is determined at the step S4704 that the predetermined time periodt2 has not elapsed, the processing returns to the step S4703, whereas ifthe predetermined time period t2 has elapsed, the protraction of theseatbelt by the DC motor 10 is stopped at a step S4705, followed byterminating the present processing.

FIG. 48 is a flowchart showing the second seatbelt slackening controlaccording to the present embodiment.

First, a PWM signal is delivered from the MPU 14 to the DC motor driver11 to rotatively drive the DC motor 10 in the seatbelt retractingdirection at a step S4801. On this occasion, the MPU 14 controls therotational speed of the DC motor 10 by varying the duty factor of thePWM signal.

More specifically,

(i) If the vehicle speed detected by the vehicle speed detector 90exceeds a predetermined value (e.g. 60 km/h), the rotational speed ofthe DC motor 10 is set to a higher value as the stepping-on force or thestepping-on speed detected by the braking detector 91 is larger orhigher.

(ii) If the detected vehicle speed exceeds a predetermined value (e.g.60 km/m) and at the same time the braking detector 91 detects that thevehicle has been braked, the rotational speed of the DC motor 10 is setto a higher value as the detected vehicle speed is higher.

(iii) If the detected vehicle speed exceeds a predetermined value (e.g.60 km/h), the rotational speed of the DC motor 10 is set to a highervalue as the rate of change in the steering angle detected by thesteering angle detector 92 is larger.

(iv) If the detected vehicle speed exceeds a predetermined value (e.g.60 km/m) and at the same time the detected rate of change in thesteering angle exceeds a predetermined value, the rotational speed ofthe DC motor 10 is set to a higher value as the detected vehicle speedis higher.

(v) If the detected vehicle speed exceeds a predetermined value (e.g. 60km/h), the rotational speed of the DC motor 10 is set to a higher valueas the ambient illuminance detected by the ambient illuminance detector93 is lower.

(vi) If the detected vehicle speed exceeds a predetermined value (e.g.60 km/h) and at the same time the detected ambient illuminance detectedby the ambient illuminance detector 93 is below a predetermined value,the rotational speed of the DC motor 10 is set to a higher value as thedetected vehicle speed is higher.

(vii) If the detected vehicle speed exceeds a predetermined value (e.g.60 km/m) and at the same time the raindrop detector 94 detectsraindrops, the rotational speed of the DC motor 10 is set to a highervalue as the detected vehicle speed is higher.

Next, it is determined at a step S4802 whether the retraction of theseatbelt has reached its limit. When the retraction of the seatbelt hasreached the limit, an improper amount of looseness has been completelyremoved.

If it is determined at the step S4802 that the retraction of theseatbelt has not reached its limit, the processing returns to the stepS4801, whereas if the retraction of the seatbelt has reached the limit,a PWM signal is delivered from the MPU 14 to the DC motor driver 11 torotatively drive the DC motor 10 in the seatbelt protracting directionat a step S4803. On this occasion as well, the MPU 14 controls therotational speed of the DC motor 10 by varying the duty factor of thePWM signal, similarly to the step S4801. Therefore, by controlling therotational speed of the DC motor 10 to a higher value according to theabove control manners (i) to (vii), the time duration of the retractionof the seatbelt at the step S4801 and the time duration of theprotraction of the seatbelt at the step S4803 become shorter, to therebyshorten the time period required to shift from an amount of loosenessgiven by the first seatbelt slackening control (hereinafter referred toas “the first amount of looseness”) to an amount of looseness given bythe second seatbelt slackening control (hereinafter referred to as “thesecond amount of looseness”).

Then, it is determined at a step S4804 whether a predetermined timeperiod t3 (e.g. 0 to 1 sec) has elapsed after the start of the drivingof the DC motor 10 in the seatbelt protracting direction. When thepredetermined time period t3 has elapsed, a proper amount of loosenesshas been given to the seatbelt and hence to the occupant. On thisoccasion, the predetermined time period t3 which is set to the timer 15is changed according to the degree of danger detected by the dangerdegree detector 89.

More specifically,

(viii) If the vehicle speed detected by the vehicle speed detector 90exceeds a predetermined value (e.g. 60 km/h), the predetermined timeperiod t3 is set to a shorter value as the stepping-on force or thestepping-on speed detected by the braking detector 91 is larger orhigher.

(ix) If the detected vehicle speed exceeds a predetermined value (e.g.60 km/m) and at the same time the braking detector 91 detects that thevehicle has been braked, the predetermined time period t3 is set to ashorter value as the detected vehicle speed is higher.

(x) If the detected vehicle speed exceeds a predetermined value (e.g. 60km/h), the predetermined time period t3 is set to a shorter value as therate of change in the steering angle detected by the steering angledetector 92 exceeds is larger.

(xi) If the detected vehicle speed exceeds a predetermined value (e.g.60 km/m) and at the same time the detected rate of change in thesteering angle exceeds a predetermined value, the predetermined timeperiod t3 is set to a shorter value as the detected vehicle speed ishigher.

(xii) If the detected vehicle speed exceeds a predetermined value (e.g.60 km/h), the predetermined time period t3 is set to a shorter value asthe ambient illuminance detected by the ambient illuminance detector 93is lower.

(xiii) If the detected vehicle speed exceeds a predetermined value (e.g.60 km/h) and at the same time the detected ambient illuminance detectedby the ambient illuminance detector 93 is below a predetermined value,the predetermined time period t3 is set to a shorter value as thedetected vehicle speed is higher.

(xiv) If the detected vehicle speed exceeds a predetermined value (e.g.60 km/m) and at the same time the raindrop detector 94 detectsraindrops, the predetermined time period t3 is set to a shorter value asthe detected vehicle speed is higher.

By shortening the predetermined time period t3 according to the abovecontrol manners (viii) to (xiv), the time duration of driving of the DCmotor 10 in the seatbelt protracting direction can be shorter, wherebythe amount of looseness of the seatbelt can be reduced.

If it is determined at the step S4804 that the predetermined time periodt3 has not elapsed, the processing returns to the step S4803, whereas ifthe predetermined time period t3 has elapsed, the protraction of theseatbelt by the DC motor 10 is terminated at a step S4805, followed byterminating the present processing.

As described above, according to the present embodiment, when nosignificant degree of danger is detected by the danger degree detector89, that is, in a normal case, the first amount of looseness is given tothe seatbelt by executing the first seatbelt slackening control, and onthe other hand, when the significant degree of danger is detected, thesecond amount of looseness is given to the seatbelt by executing thesecond seatbelt slackening control (first amount of looseness>secondamount of looseness). As a result, a comfortable seatbelt attachingenvironment can be provided while the occupant can be properlyprotected.

Thirteenth Embodiment

FIG. 49 shows the arrangement of an automotive passenger restraint andprotection apparatus according to a thirteenth embodiment of theinvention. An electric retractor provided in the present embodiment isidentical in construction with the electric retractor 100 of FIG. 1,illustration and description of which are therefore omitted.

Connected to a supply voltage input terminal of the electric retractor100 are one of contacts 102 a of a relay 102, an emitter of a transistor103, and an anode of a diode 101.

The other contact of the relay 102, one end of a coil 102 b of the relay102, and a collector of the transistor 103 are connected to a positiveterminal of a battery 105, with the other end of the coil 102 b of therelay 102 being connected to one end of a resistance 106.

The other end of the resistance 106′ is connected to one end of aseating switch 104 for detecting seating of the occupant on the seat,with the other end of the seating switch 104 being grounded. The battery105 has a negative terminal thereof grounded.

The diode 101 has a cathode thereof connected to the MPU 14 as well asto the buckle connector detector 16.

Connected to the MPU 14 are the electric retractor 100, buckleconnection detector 16, seating switch 79, and a base of the transistor103 such that the MPU 14 monitors and controls these components.

The seating switch 104 is provided in a seat of the automotive vehicleat a location below the occupant sitting on the seat (sitting portion),as shown in FIGS. 50 and 51. The seating switch 104 may be arranged atany other location such as the back portion of the seat or at both thesitting portion and the back portion.

FIG. 52 shows the construction of the seating switch 104. The seatingswitch 104 is comprised of a fixed electrode 107, and a deformableelectrode 108 formed of an elastic material and disposed above the fixedelectrode 107 in normally spaced relation thereto. The deformableelectrode 108 is secured to an insulating member 109. Lead wires 110 aand 110 b are connected to the electrodes 107 and 108, respectively.

The deformable electrode 108 is arranged in the seat at a location wherethe occupant sits on the seat (sitting portion). The electrode 108 isdeformed into contact with the fixed electrode 107 due to the weight ofthe occupant when the occupant sits on the seat, whereby current flowsthrough one of the lead wires 110 a, 110 b, the electrodes 107, 108, andthe other lead wire 110 a 110 b.

The control operation of the automotive passenger restraint andprotection apparatus according to the present embodiment constructed asabove will now be described with reference to FIG. 49.

When the occupant does not sit on the seat, the seating switch 104 isoff, and accordingly no current flows from the battery 105 to the coil102 b of the relay 102, with the contacts 102 a being open, whereby nosupply voltage is delivered from the battery 105 to the electricretractor 100, MPU 14, and buckle connection detector 16.

Thereafter, when the occupant sits down on the seat, the seating switch104 is turned on, and accordingly current flows from the battery 105 tothe coil 102 b of the relay 102 to close the contacts 102 a, wherebysupply voltage is delivered from the battery 105 to the electricretractor 100, MPU 14, and buckle connection detector 16. Then, the MPUdetects voltage applied to the seating switch 104 to thereby monitor onand off states of the seating switch 104.

Subsequently, when the occupant stands up from the seat, the seatingswitch 104 is turned off, and accordingly supply of current from thebattery 105 to the coil 102 a of the relay 102 is stopped, whereby thecontacts 102 a of the relay 102 are opened with a time lag of 10 ms, forexample, so that the delivery of supply voltage from the battery 105 tothe electric retractor 100, MPU 14, and buckle connection detector 16 isstopped.

Simultaneously upon the turning-off of the seating switch 104, the MPU14 delivers a high-level signal to the base of the transistor 103 toturn the same on, whereby supply voltage from the battery 105 issupplied via the transistor 103 to the electric retractor 100, MPU 14,and buckle connection detector 16.

When a predetermined time period (e.g. 1 minute) within which theretraction of the seatbelt can be completed by the electric retractor100 has elapsed after the MPU 14 delivered the high-level signal to thebase of the transistor 103, the MPU 14 delivers a low-level signal tothe base of the transistor 103 to turn the same off, whereby the supplyof the supply voltage from the battery 105 to the electric retractor100, MPU 14, and buckle connection detector 16 is stopped.

Thus, the supply of supply voltage from the battery 105 is carried outonly when the occupants is seated on the seat, to thereby prevent thebattery from being wastefully consumed and deteriorated, overcoming thedisadvantage with the conventional electric retractor that supplyvoltage from the battery to the electric retractor is carried out evenwhen it is not needed. Further, since the seatbelt is retracted when theseatbelt is disconnected from the buckle, it can be prevented that theseatbelt tongue is caught in the door.

As described above, according to the present embodiment, when theoccupant sits on the seat, the seating switch 104 becomes on to closethe relay 102, whereby supply voltage from the battery 105 is suppliedto the electric retractor 100, etc., and when the occupant stands upfrom the seat, the seating switch 104 becomes off to open the relay 102,whereby the supply of supply voltage from the battery to the electricretractor, etc. is stopped. As a result, wasteful consumption anddeterioration of the battery can be prevented.

Further, simultaneously when the seating switch 104 is turned off, theMPU 14 causes the transistor 103 to be turned on to supply the supplyvoltage from the battery 105 to the electric retractor 100, etc., andthen, after the lapse of a predetermined time period within which theretraction of the seatbelt by the electric retractor 100 can becompleted, the MPU 14 causes the transistor 103 to be turned off to stopthe supply of the supply voltage. As a result, retraction of theseatbelt can be carried out without fail when the seatbelt isdisconnected from the occupant, to thereby prevent the seatbelt frombeing caught in the door.

Although in the present embodiment, when a predetermined time period(e.g. 1 minute) after the occupant leaves the seat, the MPU 14 turns thetransistor 103 off, alternatively, when the occupant stands up from theseat, if voltage applied to the seating switch 104 is equal to apredetermined value (e.g. 7 volts) or less, for example, the buckleconnection detector 16 may detect whether the seatbelt tongue isattached to the buckle, and if it is attached to the buckle, the MPU 14may keep the transistor 103 on for 3 minutes, while if the seatbelttongue is not attached to the buckle, the MPU 14 may keep the transistor103 on for 30 seconds.

Further, although in the present embodiment, the supply of power to theelectric retractor and stoppage of the same are carried out dependingupon on and off states of the seating switch, they may be carried outdepending upon on and off states of an ignition switch of the engineconnected to the battery, opening and closure of the door, whether thevehicle speed is equal to 0, whether the parking brake is operated,whether the magnitude of vibration of the vehicle is below apredetermined value, whether noise volume of the vehicle engine is belowa predetermined value, whether the engine noise has a frequencydistribution other than a predetermined frequency distribution, orwhether temperature within the engine compartment of the vehicle isbelow a predetermined value.

The automotive passenger restraint and protection apparatuses accordingto the above described embodiments may be provided at any of the drivingseat, the assistant driving seat, and the back seats.

1. An automotive passenger restraint and protection apparatus for anautomotive vehicle, having a seatbelt, for restraining an occupant ofthe automotive vehicle by the seatbelt to protect the occupant,comprising: an electric retractor having driving means for retractingand protracting the seatbelt; power supply means for supplying power tosaid electric retractor; detecting means for detecting information usedfor deciding whether supply of power from said power supply means tosaid electric retractor is carried out or stoppage of the supply ofpower is carried out; first switching means responsive to results ofdetection of said detecting means, for selecting supply of power fromsaid power supply means to said electric retractor and stoppage of thesupply of power; second switching means for selecting supply of powerfrom said power supply means to said electric retractor and stoppage ofthe supply of power; and monitor control means for monitoring theresults of detection of said detecting means and controlling said secondswitching means in response to the results of detection of saiddetecting means; wherein said monitor control means controls said secondswitching means so as to select supply of power from said power supplymeans to said electric retractor, when said first switching meansselects stoppage of the supply of power from said power supply means tosaid electric retractor after supply of power from said power supplymeans to said electric retractor, and thereafter, said monitor controlmeans controls said second switching means so as to select stoppage ofthe supply of power from said power supply means to said electricretractor after a lapse of a predetermined time period from the supplyof power being selected by said second switching means.